On Conditional Bias and Correlation: A Guest Post

After I posted about “Observational Systems: Correlations with Value-Added and Bias,” a blog follower, associate professor, and statistician named Laura Ring Kapitula (see also a very influential article she wrote on VAMs here) posted comments on this site that I found of interest, and I thought would also be of interest to blog followers. Hence, I invited her to write a guest post, and she did.

She used R (i.e., a free software environment for statistical computing and graphics) to simulate correlation scatterplots (see Figures below) to illustrate three unique situations: (1) a simulation where there are two indicators (e.g., teacher value-added and observational estimates plotted on the x and y axes) that have a correlation of r = 0.28 (the highest correlation coefficient at issue in the aforementioned post); (2) a simulation exploring the impact of negative bias and a moderate correlation on a group of teachers; and (3) another simulation with two indicators that have a non-linear relationship possibly induced or caused by bias. She designed simulations (2) and (3) to illustrate the plausibility of the situation suggested next (as written into Audrey’s post prior) about potential bias in both value-added and observational estimates:

If there is some bias present in value-added estimates, and some bias present in the observational estimates…perhaps this is why these low correlations are observed. That is, only those teachers teaching classrooms inordinately stacked with students from racial minority, poor, low achieving, etc. groups might yield relatively stronger correlations between their value-added and observational scores given bias, hence, the low correlations observed may be due to bias and bias alone.

Laura continues…

Here, Audrey makes the point that a correlation of r = 0.28 is “weak.” It is, accordingly, useful to see an example of just how “weak” such a correlation is by looking at a scatterplot of data selected from a population where the true correlation is r = 0.28. To make the illustration more meaningful the points are colored based on their quintile scores as per simulated teachers’ value-added divided into the lowest 20%, next 20%, etc.

In this figure you can see by looking at the blue “least squares line” that, “on average,” as a simulated teacher’s value-added estimate increases the average of a teacher’s observational estimate increases. However, there is a lot of variability (or scatter points) around the (scatterplot) line. Given this variability, we can make statements about averages, such as “on average” teachers in the top 20% for VAM scores will likely have on average higher observed observational scores; however, there is not nearly enough precision to make any (and certainly not any good) predictions about the observational score from the VAM score for individual teachers. In fact, the linear relationship between teachers’ VAM and observational scores only accounts for about 8% of the variation in VAM score. Note: we get 8% by squaring the aforementioned r = 0.28 correlation (i.e., an R squared). The other 92% of the variance is due to error and other factors.

What this means in practice is that when correlations are this “weak,” it is reasonable to say statements about averages, for example, that “on average” as one variable increases the mean of the other variable increases, but it would not be prudent or wise to make predictions for individuals based on these data. See, for example, that individuals in the top 20% (quintile 5) of VAM have a very large spread in their scores on the observational score, with 95% of the scores in the top quintile being in between the 7th and 98th percentiles for their observational scores. So, here if we observe a VAM for a specific teacher in the top 20%, and we do not know their observational score, we cannot say much more than their observational score is likely to be in the top 90%. Similarly, if we observe a VAM in the bottom 20%, we cannot say much more than their observational score is likely to be somewhere in the bottom 90%. That’s not saying a lot, in terms of precision, but also in terms of practice.

The second scatterplot I ran to test how bias that only impacts a small group of teachers might theoretically impact an overall correlation, as posited by Audrey. Here I simulated a situation where, again, there are two values present in a population of teachers: a teacher’s value-added and a teacher’s observational score. Then I insert a group of teachers (as Audrey described) who represent 20% of a population and teach a disproportionate number of students who come from relatively lower socioeconomic, high racial minority, etc. backgrounds, and I assume this group is measured with negative bias on both indicators and this group has a moderate correlation between indicators of r = 0.50. The other 80% of the population is assumed to be uncorrelated. Note: for this demonstration I assume that this group includes 20% of teachers from the aforementioned population, these teachers I assume to be measured with negative bias (by one standard deviation on average) on both measures, and, again, I set their correlation at r = 0.50 with the other 80% of teachers at a correlation of zero.

What you can see is that if there is bias in this correlation that impacts only a certain group on the two instrument indicators; hence, it is possible that this bias can result in an observed correlation overall. In other words, a strong correlation noted in just one group of teachers (i.e., teachers scoring the lowest on their value-added and observational indicators in this case) can be relatively stronger than the “weak” correlation observed on average or overall.

Another, possible situation is that there might be a non-linear relationship between these two measures. In the simulation below, I assume that different quantiles on VAM have a different linear relationship with the observational score. For example, in the plot there is not a constant slope, but teachers who are in the first quintile on VAM I assume to have a correlation of r = 0.50 with observational scores, the second quintile I assume to have a correlation of r = 0.20, and the other quintiles I assume to be uncorrelated. This results in an overall correlation in the simulation of r = 0.24, with a very small p-value (i.e. a very small chance that a correlation of this size would be observed by random chance alone if the true correlation was zero).

What this means in practice is that if, in fact, there is a non-linear relationship between teachers’ observational and VAM scores, this can induce a small but statistically significant correlation. As evidenced, teachers in the lowest 20% on the VAM score have differences in the mean observational score depending on the VAM score (a moderate correlation of r = 0.50), but for the other 80%, knowing the VAM score is not informative as there is a very small correlation for the second quintile and no correlation for the upper 60%. So, if quintile cut-off scores are used, teachers can easily be misclassified. In sum, Pearson Correlations (the standard correlation coefficient) measure the overall strength of  linear relationships between X and Y, but if X and Y have a non-linear relationship (like as illustrated in the above), this statistic can be very misleading.

Note also that for all of these simulations very small p-values are observed (e.g., p-values <0.0000001 which, again, mean these correlations are statistically significant or that the probability of observing correlations this large by chance if the true correlation is zero, is nearly 0%). What this illustrates, again, is that correlations (especially correlations this small) are (still) often misleading. While they might be statistically significant, they might mean relatively little in the grand scheme of things (i.e., in terms of practical significance; see also “The Difference Between”Significant’ and ‘Not Significant’ is not Itself Statistically Significant” or posts on Andrew Gelman’s blog for more discussion on these topics if interested).

At the end of the day r = 0.28 is still a “weak” correlation. In addition, it might be “weak,” on average, but much stronger and statistically and practically significant for teachers in the bottom quintiles (e.g., teachers in the bottom 20%, as illustrated in the final figure above) typically teaching the highest needs students. Accordingly, this might be due, at least in part, to bias.

In conclusion, one should always be wary of claims based on “weak” correlations, especially if they are positioned to be stronger than industry standards would classify them (e.g., in the case highlighted in the prior post). Even if a correlation is “statistically significant,” it is possible that the correlation is the result of bias, and that the relationship is so weak that it is not meaningful in practice, especially when the goal is to make high-stakes decisions about individual teachers. Accordingly, when you see correlations this small, keep these scatterplots in mind or generate some of your own (see, for example, here to dive deeper into what these correlations might mean and how significant these correlations might really be).

*Please contact Dr. Kapitula directly at kapitull@gvsu.edu if you want more information or to access the R code she used for the above.

The “Widget Effect” Report Revisited

You might recall that in 2009, The New Teacher Project published a highly influential “Widget Effect” report in which researchers (see citation below) evidenced that 99% of teachers (whose teacher evaluation reports they examined across a sample of school districts spread across a handful of states) received evaluation ratings of “satisfactory” or higher. Inversely, only 1% of the teachers whose reports researchers examined received ratings of “unsatisfactory,” even though teachers’ supervisors could identify more teachers whom they deemed ineffective when asked otherwise.

Accordingly, this report was widely publicized given the assumed improbability that only 1% of America’s public school teachers were, in fact, ineffectual, and given the fact that such ineffective teachers apparently existed but were not being identified using standard teacher evaluation/observational systems in use at the time.

Hence, this report was used as evidence that America’s teacher evaluation systems were unacceptable and in need of reform, primarily given the subjectivities and flaws apparent and arguably inherent across the observational components of these systems. This reform was also needed to help reform America’s public schools, writ large, so the logic went and (often) continues to go. While binary constructions of complex data such as these are often used to ground simplistic ideas and push definitive policies, ideas, and agendas, this tactic certainly worked here, as this report (among a few others) was used to inform the federal and state policies pushing teacher evaluation system reform as a result (e.g., Race to the Top (RTTT)).

Likewise, this report continues to be used whenever a state’s or district’s new-and-improved teacher evaluation systems (still) evidence “too many” (as typically arbitrarily defined) teachers as effective or higher (see, for example, an Education Week article about this here). Although, whether in fact the systems have actually been reformed is also of debate in that states are still using many of the same observational systems they were using prior (i.e., not the “binary checklists” exaggerated in the original as well as this report, albeit true in the case of the district of focus in this study). The real “reforms,” here, pertained to the extent to which value-added model (VAM) or other growth output were combined with these observational measures, and the extent to which districts adopted state-level observational models as per the centralized educational policies put into place at the same time.

Nonetheless, now eight years later, Matthew A. Kraft – an Assistant Professor of Education & Economics at Brown University and Allison F. Gilmour – an Assistant Professor at Temple University (and former doctoral student at Vanderbilt University), revisited the original report. Just published in the esteemed, peer-reviewed journal Educational Researcher (see an earlier version of the published study here), Kraft and Gilmour compiled “teacher performance ratings across 24 [of the 38, including 14 RTTT] states that [by 2014-2015] adopted major reforms to their teacher evaluation systems” as a result of such policy initiatives. They found that “the percentage of teachers rated Unsatisfactory remains less than 1%,” except for in two states (i.e., Maryland and New Mexico), with Unsatisfactory (or similar) ratings varying “widely across states with 0.7% to 28.7%” as the low and high, respectively (see also the study Abstract).

Related, Kraft and Gilmour found that “some new teacher evaluation systems do differentiate among teachers, but most only do so at the top of the ratings spectrum” (p. 10). More specifically, observers in states in which teacher evaluation ratings include five versus four rating categories differentiate teachers more, but still do so along the top three ratings, which still does not solve the negative skew at issue (i.e., “too many” teachers still scoring “too well”). They also found that when these observational systems were used for formative (i.e., informative, improvement) purposes, teachers’ ratings were lower than when they were used for summative (i.e., final summary) purposes.

Clearly, the assumptions of all involved in this area of policy research come into play, here, akin to how they did in The Bell Curve and The Bell Curve Debate. During this (still ongoing) debate, many fervently debated whether socioeconomic and educational outcomes (e.g., IQ) should be normally distributed. What this means in this case, for example, is that for every teacher who is rated highly effective there should be a teacher rated as highly ineffective, more or less, to yield a symmetrical distribution of teacher observational scores across the spectrum.

In fact, one observational system of which I am aware (i.e., the TAP System for Teacher and Student Advancement) is marketing its proprietary system, using as a primary selling point figures illustrating (with text explaining) how clients who use their system will improve their prior “Widget Effect” results (i.e., yielding such normal curves; see Figure below, as per Jerald & Van Hook, 2011, p. 1).

Evidence also suggests that these scores are also (sometimes) being artificially deflated to assist in these attempts (see, for example, a recent publication of mine released a few days ago here in the (also) esteemed, peer-reviewed Teachers College Record about how this is also occurring in response to the “Widget Effect” report and the educational policies that follows).

While Kraft and Gilmour assert that “systems that place greater weight on normative measures such as value-added scores rather than…[just]…observations have fewer teachers rated proficient” (p. 19; see also Steinberg & Kraft, forthcoming; a related article about how this has occurred in New Mexico here; and New Mexico’s 2014-2016 data below and here, as also illustrative of the desired normal curve distributions discussed above), I highly doubt this purely reflects New Mexico’s “commitment to putting students first.”

I also highly doubt that, as per New Mexico’s acting Secretary of Education, this was “not [emphasis added] designed with quote unquote end results in mind.” That is, “the New Mexico Public Education Department did not set out to place any specific number or percentage of teachers into a given category.” If true, it’s pretty miraculous how this simply worked out as illustrated… This is also at issue in the lawsuit in which I am involved in New Mexico, in which the American Federation of Teachers won an injunction in 2015 that still stands today (see more information about this lawsuit here). Indeed, as per Kraft, all of this “might [and possibly should] undercut the potential for this differentiation [if ultimately proven artificial, for example, as based on statistical or other pragmatic deflation tactics] to be seen as accurate and valid” (as quoted here).

Notwithstanding, Kraft and Gilmour, also as part (and actually the primary part) of this study, “present original survey data from an urban district illustrating that evaluators perceive more than three times as many teachers in their schools to be below Proficient than they rate as such.” Accordingly, even though their data for this part of this study come from one district, their findings are similar to others evidenced in the “Widget Effect” report; hence, there are still likely educational measurement (and validity) issues on both ends (i.e., with using such observational rubrics as part of America’s reformed teacher evaluation systems and using survey methods to put into check these systems, overall). In other words, just because the survey data did not match the observational data does not mean either is wrong, or right, but there are still likely educational measurement issues.

Also of issue in this regard, in terms of the 1% issue, is (a) the time and effort it takes supervisors to assist/desist after rating teachers low is sometimes not worth assigning low ratings; (b) how supervisors often give higher ratings to those with perceived potential, also in support of their future growth, even if current evidence suggests a lower rating is warranted; (c) how having “difficult conversations” can sometimes prevent supervisors from assigning the scores they believe teachers may deserve, especially if things like job security are on the line; (d) supervisors’ challenges with removing teachers, including “long, laborious, legal, draining process[es];” and (e) supervisors’ challenges with replacing teachers, if terminated, given current teacher shortages and the time and effort, again, it often takes to hire (ideally more qualified) replacements.

References:

Jerald, C. D., & Van Hook, K. (2011). More than measurement: The TAP system’s lessons learned for designing better teacher evaluation systems. Santa Monica, CA: National Institute for Excellence in Teaching (NIET). Retrieved from http://files.eric.ed.gov/fulltext/ED533382.pdf

Kraft, M. A, & Gilmour, A. F. (2017). Revisiting the Widget Effect: Teacher evaluation reforms and the distribution of teacher effectiveness. Educational Researcher, 46(5) 234-249. doi:10.3102/0013189X17718797

Steinberg, M. P., & Kraft, M. A. (forthcoming). The sensitivity of teacher performance ratings to the design of teacher evaluation systems. Educational Researcher.

Weisberg, D., Sexton, S., Mulhern, J., & Keeling, D. (2009). “The Widget Effect.” Education Digest, 75(2), 31–35.

The Tripod Student Survey Instrument: Its Factor Structure and Value-Added Correlations

The Tripod student perception survey instrument is a “research-based” instrument increasingly being used by states to add to state’s teacher evaluation systems as based on “multiple measures.” While there are other instruments also in use, as well as student survey instruments being developed by states and local districts, this one in particular is gaining in popularity, also in that it was used throughout the Bill & Melinda Gates Foundation’s ($43 million worth of) Measures of Effective Teaching (MET) studies. A current estimate (as per the study discussed in this post) is that during the 2015–2016 school year approximately 1,400 schools purchased and administered the Tripod. See also a prior post (here) about this instrument, or more specifically a chapter of a book about the instrument as authored by the instrument’s developer and lead researcher in a  research surrounding it – Ronald Ferguson.

In a study recently released in the esteemed American Educational Research Journal (AERJ), and titled “What Can Student Perception Surveys Tell Us About Teaching? Empirically Testing the Underlying Structure of the Tripod Student Perception Survey,” researchers found that the Tripod’s factor structure did not “hold up.” That is, Tripod’s 7Cs (i.e., seven constructs including: Care, Confer, Captivate, Clarify, Consolidate, Challenge, Classroom Management; see more information about the 7Cs here) and the 36 items that are positioned within each of the 7Cs did not fit the 7C framework as theorized by instrument developer(s).

Rather, using the MET database (N=1,049 middle school math class sections; N=25,423 students), researchers found that an alternative bi-factor structure (i.e., two versus seven constructs) best fit the Tripod items theoretically positioned otherwise. These two factors included (1) a general responsivity dimension that includes all items (more or less) unrelated to (2) a classroom management dimension that governs responses on items surrounding teachers’ classroom management. Researchers were unable to to distinguish across items seven separate dimensions.

Researchers also found that the two alternative factors noted — general responsivity and classroom management — were positively associated with teacher value-added scores. More specifically, results suggested that these two factors were positively and statistically significantly associated with teachers’ value-added measures based on state mathematics tests (standardized coefficients were .25 and .25, respectively), although for undisclosed reasons, results apparently suggested nothing about these two factors’ (cor)relationships with value-added estimates base on state English/language arts (ELA) tests. As per authors’ findings in the area of mathematics, prior researchers have also found low to moderate agreement between teacher ratings and student perception ratings; hence, this particular finding simply adds another source of convergent evidence.

Authors do give multiple reasons and plausible explanations as to why they found what they did that you all can read in more depth via the full article, linked to above and fully cited below. Authors also note that “It is unclear whether the original 7Cs that describe the Tripod instrument were intended to capture seven distinct dimensions on which students can reliably discriminate among teachers or whether the 7Cs were merely intended to be more heuristic domains that map out important aspects of teaching” (p. 1859); hence, this is also important to keep in mind given study findings.

As per study authors, and to their knowledge, “this study [was] the first to systematically investigate the multidimensionality of the Tripod student perception survey” (p. 1863).

Citation: Wallace, T. L., Kelcey, B., &  Ruzek, E. (2016). What can student perception surveys tell us about teaching? Empirically testing the underlying structure of the Tripod student perception survey.  American Educational Research Journal, 53(6), 1834–1868.
doiI:10.3102/0002831216671864 Retrieved from http://journals.sagepub.com/doi/pdf/10.3102/0002831216671864

New Texas Lawsuit: VAM-Based Estimates as Indicators of Teachers’ “Observable” Behaviors

Last week I spent a few days in Austin, one day during which I provided expert testimony for a new state-level lawsuit that has the potential to impact teachers throughout Texas. The lawsuit — Texas State Teachers Association (TSTA) v. Texas Education Agency (TEA), Mike Morath in his Official Capacity as Commissioner of Education for the State of Texas.

The key issue is that, as per the state’s Texas Education Code (Sec. § 21.351, see here) regarding teachers’ “Recommended Appraisal Process and Performance Criteria,” The Commissioner of Education must adopt “a recommended teacher appraisal process and criteria on which to appraise the performance of teachers. The criteria must be based on observable, job-related behavior, including: (1) teachers’ implementation of discipline management procedures; and (2) the performance of teachers’ students.” As for the latter, the State/TEA/Commissioner defined, as per its Texas Administrative Code (T.A.C., Chapter 15, Sub-Chapter AA, §150.1001, see here), that teacher-level value-added measures should be treated as one of the four measures of “(2) the performance of teachers’ students;” that is, one of the four measures recognized by the State/TEA/Commissioner as an “observable” indicator of a teacher’s “job-related” performance.

While currently no district throughout the State of Texas is required to use a value-added component to assess and evaluate its teachers, as noted, the value-added component is listed as one of four measures from which districts must choose at least one. All options listed in the category of “observable” indicators include: (A) student learning objectives (SLOs); (B) student portfolios; (C) pre- and post-test results on district-level assessments; and (D) value-added data based on student state assessment results.

Related, the state has not recommended or required that any district, if the value-added option is selected, to choose any particular value-added model (VAM) or calculation approach. Nor has it recommended or required that any district adopt any consequences as attached to these output; however, things like teacher contract renewal and sharing teachers’ prior appraisals with other districts in which teachers might be applying for new jobs is not discouraged. Again, though, the main issue here (and the key points to which I testified) was that the value-added component is listed as an “observable” and “job-related” teacher effectiveness indicator as per the state’s administrative code.

Accordingly, my (5 hour) testimony was primarily (albeit among many other things including the “job-related” part) about how teacher-level value-added data do not yield anything that is observable in terms of teachers’ effects. Likewise, officially referring to these data in this way is entirely false, in fact, in that:

  • “We” cannot directly observe a teacher “adding” (or detracting) value (e.g., with our own eyes, like supervisors can when they conduct observations of teachers in practice);
  • Using students’ test scores to measure student growth upwards (or downwards) and over time, as is very common practice using the (very often instructionally insensitive) state-level tests required by No Child Left Behind (NCLB), and doing this once per year in mathematics and reading/language arts (that includes prior and other current teachers’ effects, summer learning gains and decay, etc.), is not valid practice. That is, doing this has not been validated by the scholarly/testing community; and
  • Worse and less valid is to thereafter aggregate this student-level growth to the teacher level and then call whatever “growth” (or the lack thereof) is because of something the teacher (and really only the teacher did), as directly “observable.” These data are far from assessing a teacher’s causal or “observable” impacts on his/her students’ learning and achievement over time. See, for example, the prior statement released about value-added data use in this regard by the American Statistical Association (ASA) here. In this statement it is written that: “Research on VAMs has been fairly consistent that aspects of educational effectiveness that are measurable and within teacher control represent a small part of the total variation [emphasis added to note that this is variation explained which = correlational versus causal research] in student test scores or growth; most estimates in the literature attribute between 1% and 14% of the total variability [emphasis added] to teachers. This is not saying that teachers have little effect on students, but that variation among teachers [emphasis added] accounts for a small part of the variation [emphasis added] in [said test] scores. The majority of the variation in [said] test scores is [inversely, 86%-99% related] to factors outside of the teacher’s control such as student and family background, poverty, curriculum, and unmeasured influences.”

If any of you have anything to add to this, please do so in the comments section of this post. Otherwise, I will keep you posted on how this goes. My current understanding is that this one will be headed to court.

Difficulties When Combining Multiple Teacher Evaluation Measures

A new study about multiple “Approaches for Combining Multiple Measures of Teacher Performance,” with special attention paid to reliability, validity, and policy, was recently published in the American Educational Research Association (AERA) sponsored and highly-esteemed Educational Evaluation and Policy Analysis journal. You can find the free and full version of this study here.

In this study authors José Felipe Martínez – Associate Professor at the University of California, Los Angeles, Jonathan Schweig – at the RAND Corporation, and Pete Goldschmidt – Associate Professor at California State University, Northridge and creator of the value-added model (VAM) at legal issue in the state of New Mexico (see, for example, here), set out to help practitioners “combine multiple measures of complex [teacher evaluation] constructs into composite indicators of performance…[using]…various conjunctive, disjunctive (or complementary), and weighted (or compensatory) models” (p. 738). Multiple measures in this study include teachers’ VAM estimates, observational scores, and student survey results.

While authors ultimately suggest that “[a]ccuracy and consistency are greatest if composites are constructed to maximize reliability,” perhaps more importantly, especially for practitioners, authors note that “accuracy varies across models and cut-scores and that models with similar accuracy may yield different teacher classifications.”

This, of course, has huge implications for teacher evaluation systems as based upon multiple measures in that “accuracy” means “validity” and “valid” decisions cannot be made as based on “invalid” or “inaccurate” data that can so arbitrarily change. In other words, what this means is that likely never will a decision about a teacher being this or that actually mean this or that. In fact, this or that might be close, not so close, or entirely wrong, which is a pretty big deal when the measures combined are assumed to function otherwise. This is especially interesting, again and as stated prior, that the third author on this piece – Pete Goldschmidt – is the person consulting with the state of New Mexico. Again, this is the state that is still trying to move forward with the attachment of consequences to teachers’ multiple evaluation measures, as assumed (by the state but not the state’s consultant?) to be accurate and correct (see, for example, here).

Indeed, this is a highly inexact and imperfect social science.

Authors also found that “policy weights yield[ed] more reliable composites than optimal prediction [i.e., empirical] weights” (p. 750). In addition, “[e]mpirically derived weights may or may not align with important theoretical and policy rationales” (p. 750); hence, the authors collectively referred others to use theory and policy when combining measures, while also noting that doing so would (a) still yield overall estimates that would “change from year to year as new crops of teachers and potentially measures are incorporated” (p. 750) and (b) likely “produce divergent inferences and judgments about individual teachers (p. 751). Authors, therefore, concluded that “this in turn highlights the need for a stricter measurement validity framework guiding the development, use, and monitoring of teacher evaluation systems” (p. 751), given all of this also makes the social science arbitrary, which is also a legal issue in and of itself, as also quasi noted.

Now, while I will admit that those who are (perhaps unwisely) devoted to the (in many ways forced) combining of these measures (despite what low reliability indicators already mean for validity, as unaddressed in this piece) might find some value in this piece (e.g., how conjunctive and disjunctive models vary, how principal component, unit weight, policy weight, optimal prediction approaches vary), I will also note that forcing the fit of such multiple measures in such ways, especially without a thorough background in and understanding of reliability and validity and what reliability means for validity (i.e., with rather high levels of reliability required before any valid inferences and especially high-stakes decisions can be made) is certainly unwise.

If high-stakes decisions are not to be attached, such nettlesome (but still necessary) educational measurement issues are of less importance. But any positive (e.g., merit pay) or negative (e.g., performance improvement plan) consequence that comes about without adequate reliability and validity should certainly cause pause, if not a justifiable grievance as based on the evidence provided herein, called for herein, and required pretty much every time such a decision is to be made (and before it is made).

Citation: Martinez, J. F., Schweig, J., & Goldschmidt, P. (2016). Approaches for combining multiple measures of teacher performance: Reliability, validity, and implications for evaluation policy. Educational Evaluation and Policy Analysis, 38(4), 738–756. doi: 10.3102/0162373716666166 Retrieved from http://journals.sagepub.com/doi/pdf/10.3102/0162373716666166

Note: New Mexico’s data were not used for analytical purposes in this study, unless any districts in New Mexico participated in the Bill & Melinda Gates Foundation’s Measures of Effective Teaching (MET) study yielding the data used for analytical purposes herein.

Another Study about Bias in Teachers’ Observational Scores

Following-up on two prior posts about potential bias in teachers’ observations (see prior posts here and here), another research study was recently released evidencing, again, that the evaluation ratings derived via observations of teachers in practice are indeed related to (and potentially biased by) teachers’ demographic characteristics. The study also evidenced that teachers representing racial and ethnic minority background might be more likely than others to not only receive lower relatively scores but also be more likely identified for possible dismissal as a result of their relatively lower evaluation scores.

The Regional Educational Laboratory (REL) authored and U.S. Department of Education (Institute of Education Sciences) sponsored study titled “Teacher Demographics and Evaluation: A Descriptive Study in a Large Urban District” can be found here, and a condensed version of the study can be found here. Interestingly, the study was commissioned by district leaders who were already concerned about what they believed to be occurring in this regard, but for which they had no hard evidence… until the completion of this study.

Authors’ key finding follows (as based on three consecutive years of data): Black teachers, teachers age 50 and older, and male teachers were rated below proficient relatively more often than the same district teachers to whom they were compared. More specifically,

  • In all three years the percentage of teachers who were rated below proficient was higher among Black teachers than among White teachers, although the gap was smaller in 2013/14 and 2014/15.
  • In all three years the percentage of teachers with a summative performance rating who were rated below proficient was higher among teachers age 50 and older than among teachers younger than age 50.
  • In all three years the difference in the percentage of male and female teachers with a summative performance rating who were rated below proficient was approximately 5 percentage points or less.
  • The percentage of teachers who improved their rating during all three year-to-year
    comparisons did not vary by race/ethnicity, age, or gender.

This is certainly something to (still) keep in consideration, especially when teachers are rewarded (e.g., via merit pay) or penalized (e.g., vie performance improvement plans or plans for dismissal). Basing these or other high-stakes decisions on not only subjective but also likely biased observational data (see, again, other studies evidencing that this is happening here and here), is not only unwise, it’s also possibly prejudiced.

While study authors note that their findings do not necessarily “explain why the
patterns exist or to what they may be attributed,” and that there is a “need
for further research on the potential causes of the gaps identified, as well as strategies for
ameliorating them,” for starters and at minimum, those conducting these observations literally across the country must be made aware.

Citation: Bailey, J., Bocala, C., Shakman, K., & Zweig, J. (2016). Teacher demographics and evaluation: A descriptive study in a large urban district. Washington DC: U.S. Department of Education. Retrieved from http://ies.ed.gov/ncee/edlabs/regions/northeast/pdf/REL_2017189.pdf

Miami-Dade, Florida’s Recent “Symbolic” and “Artificial” Teacher Evaluation Moves

Last spring, Eduardo Porter – writer of the Economic Scene column for The New York Times – wrote an excellent article, from an economics perspective, about that which is happening with our current obsession in educational policy with “Grading Teachers by the Test” (see also my prior post about this article here; although you should give the article a full read; it’s well worth it). In short, though, Porter wrote about what economist’s often refer to as Goodhart’s Law, which states that “when a measure becomes the target, it can no longer be used as the measure.” This occurs given the great (e.g., high-stakes) value (mis)placed on any measure, and the distortion (i.e., in terms of artificial inflation or deflation, depending on the desired direction of the measure) that often-to-always comes about as a result.

Well, it’s happened again, this time in Miami-Dade, Florida, where the Miami-Dade district’s teachers are saying its now “getting harder to get a good evaluation” (see the full article here). Apparently, teachers evaluation scores, from last to this year, are being “dragged down,” primarily given teachers’ students’ performances on tests (as well as tests of subject areas that and students whom they do not teach).

“In the weeks after teacher evaluations for the 2015-16 school year were distributed, Miami-Dade teachers flooded social media with questions and complaints. Teachers reported similar stories of being evaluated based on test scores in subjects they don’t teach and not being able to get a clear explanation from school administrators. In dozens of Facebook posts, they described feeling confused, frustrated and worried. Teachers risk losing their jobs if they get a series of low evaluations, and some stand to gain pay raises and a bonus of up to $10,000 if they get top marks.”

As per the figure also included in this article, see the illustration of how this is occurring below; that is, how it is becoming more difficult for teachers to get “good” overall evaluation scores but also, and more importantly, how it is becoming more common for districts to simply set different cut scores to artificially increase teachers’ overall evaluation scores.

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“Miami-Dade say the problems with the evaluation system have been exacerbated this year as the number of points needed to get the “highly effective” and “effective” ratings has continued to increase. While it took 85 points on a scale of 100 to be rated a highly effective teacher for the 2011-12 school year, for example, it now takes 90.4.”

This, as mentioned prior, is something called “artificial deflation,” whereas the quality of teaching is likely not changing nearly to the extent the data might illustrate it is. Rather, what is happening behind the scenes (e.g., the manipulation of cut scores) is giving the impression that indeed the overall teacher system is in fact becoming better, more rigorous, aligning with policymakers’ “higher standards,” etc).

This is something in the educational policy arena that we also call “symbolic policies,” whereas nothing really instrumental or material is happening, and everything else is a facade, concealing a less pleasant or creditable reality that nothing, in fact, has changed.

Citation: Gurney, K. (2016). Teachers say it’s getting harder to get a good evaluation. The school district disagrees. The Miami Herald. Retrieved from http://www.miamiherald.com/news/local/education/article119791683.html#storylink=cpy

Ohio Rejects Subpar VAM, for Another VAM Arguably Less Subpar?

From a prior post coming from Ohio (see here), you may recall that Ohio state legislators recently introduced a bill to review its state’s value-added model (VAM), especially as it pertains to the state’s use of their VAM (i.e., the Education Value-Added Assessment System (EVAAS); see more information about the use of this model in Ohio here).

As per an article published last week in The Columbus Dispatch, the Ohio Department of Education (ODE) apparently rejected a proposal made by the state’s pro-charter school Ohio Coalition for Quality Education and the state’s largest online charter school, all of whom wanted to add (or replace) this state’s VAM with another, unnamed “Similar Students” measure (which could be the Student Growth Percentiles model discussed prior on this blog, for example, here, here, and here) used in California.

The ODE charged that this measure “would lower expectations for students with different backgrounds, such as those in poverty,” which is not often a common criticism of this model (if I have the model correct), nor is it a common criticism of the model they already have in place. In fact, and again if I have the model correct, these are really the only two models that do not statistically control for potentially biasing factors (e.g., student demographic and other background factors) when calculating teachers’ value-added; hence, their arguments about this model may be in actuality no different than that which they are already doing. Hence, statements like that made by Chris Woolard, senior executive director of the ODE, are false: “At the end of the day, our system right now has high expectations for all students. This (California model) violates that basic principle that we want all students to be able to succeed.”

The models, again if I am correct, are very much the same. While indeed the California measurement might in fact consider “student demographics such as poverty, mobility, disability and limited-English learners,” this model (if I am correct on the model) does not statistically factor these variables out. If anything, the state’s EVAAS system does, even though EVAAS modelers claim they do not do this, by statistically controlling for students’ prior performance, which (unfortunately) has these demographics already built into them. In essence, they are already doing the same thing they now protest.

Indeed, as per a statement made by Ron Adler, president of the Ohio Coalition for Quality Education, not only is it “disappointing that ODE spends so much time denying that poverty and mobility of students impedes their ability to generate academic performance…they [continue to] remain absolutely silent about the state’s broken report card and continually defend their value-added model that offers no transparency and creates wild swings for schools across Ohio” (i.e., the EVAAS system, although in all fairness all VAMs and the SGP yield the “wild swings’ noted). See, for example, here.

What might be worse, though, is that the ODE apparently found that, depending on the variables used in the California model, it produced different results. Guess what! All VAMs, depending on the variables used, produce different results. In fact, using the same data and different VAMs for the same teachers at the same time also produce (in some cases grossly) different results. The bottom line here is if any thinks that any VAM is yielding estimates from which valid or “true” statements can be made are fooling themselves.

Bias in Teacher Observations, As Well

Following a post last month titled “New Empirical Evidence: Students’ ‘Persistent Economic Disadvantage’ More Likely to Bias Value-Added Estimates,” Matt Barnum — senior staff writer for The 74, an (allegedly) non-partisan, honest, and fact-based news site backed by Editor-in-Chief Campbell Brown and covering America’s education system “in crisis” (see, also, a prior post about The 74 here) — followed up with a tweet via Twitter. He wrote: “Yes, though [bias caused by economic disadvantage] likely applies with equal or even more force to other measures of teacher quality, like observations.” I replied via Twitter that I disagreed with this statement in that I was unaware of research in support of his assertion, and Barnum sent me two articles to review thereafter.

I attempted to review both of these articles herein, although I quickly figured out that I had actually read and reviewed the first (2014) piece on this blog (see original post here, see also a 2014 Brookings Institution article summarizing this piece here). In short, in this study researchers found that the observational components of states’ contemporary teacher systems certainly “add” more “value” than their value-added counterparts, especially for (in)formative purposes. However, researchers  found that observational bias also exists, as akin to value-added bias, whereas teachers who are non-randomly assigned students who enter their classrooms with higher levels of prior achievement tend to get higher observational scores than teachers non-randomly assigned students entering their classrooms with lower levels of prior achievement. Researchers concluded that because districts “do not have processes in place to address the possible biases in observational scores,” statistical adjustments might be made to offset said bias, as might external observers/raters be brought in to yield more “objective” observational assessments of teachers.

For the second study, and this post here, I gave this one a more thorough read (you can find the full study, pre-publication here). Using data from the Measures of Effective
Teaching (MET) Project, in which random assignment was used (or more accurately attempted), researchers also explored the extent to which students enrolled in teachers’ classrooms influence classroom observational scores.

They found, primarily, that:

  1. “[T]he context in which teachers work—most notably, the incoming academic performance of their students—plays a critical role in determining teachers’ performance” as measured by teacher observations. More specifically, “ELA [English/language arts] teachers were more than twice as likely to be rated in the top performance quintile if [nearly randomly] assigned the highest achieving students compared with teachers assigned the low-est achieving students,” and “math teachers were more than 6 times as likely.” In addition, “approximately half of the teachers—48% in ELA and 54% in math—were rated in the top two performance quintiles if assigned the highest performing students, while 37% of ELA and only 18% of math teachers assigned the lowest performing students were highly rated based on classroom observation scores”
  2. “[T]he intentional sorting of teachers to students has a significant influence on measured performance” as well. More specifically, results further suggest that “higher performing students [are, at least sometimes] endogenously sorted into the classes of higher performing teachers…Therefore, the nonrandom and positive assignment of teachers to classes of students based on time-invariant (and unobserved) teacher
    characteristics would reveal more effective teacher performance, as measured by classroom observation scores, than may actually be true.”

So, the non-random assignment of teachers biases both the value-added and observational components written into America’s now “more objective” teacher evaluation systems, as (formerly) required of all states that were to comply with federal initiatives and incentives (e.g., Race to the Top). In addition, when those responsible for assigning students to classrooms (sub)consciously favor teachers with high, prior observational scores, this exacerbates the issues. This is especially important when observational (and value-added) data are to be used for high-stakes accountability systems in that the data yielded via really both measurement systems may be less likely to reflect “true” teaching effectiveness due to “true” bias. “Indeed, teachers working with higher achieving students tend to receive higher performance ratings, above and beyond that which might be attributable to aspects of teacher quality,” and vice-versa.

Citation Study #1: Whitehurst, G. J., Chingos, M. M., & Lindquist, K. M. (2014). Evaluating teachers with classroom observations: Lessons learned in four districts. Washington, DC: Brookings Institution. Retrieved from https://www.brookings.edu/wp-content/uploads/2016/06/Evaluating-Teachers-with-Classroom-Observations.pdf

Citation Study #2: Steinberg, M. P., & Garrett, R. (2016). Classroom composition and measured teacher performance: What do teacher observation scores really measure? Educational Evaluation and Policy Analysis, 38(2), 293-317. doi:10.3102/0162373715616249  Retrieved from http://static.politico.com/58/5f/f14b2b144846a9b3365b8f2b0897/study-of-classroom-observations-of-teachers.pdf

 

VAM-Based Chaos Reigns in Florida, as Caused by State-Mandated Teacher Turnovers

The state of Florida is another one of our state’s to watch in that, even since the passage of the Every Student Succeeds Act (ESSA) last January, the state is still moving forward with using its VAMs for high-stakes accountability reform. See my most recent post about one district in Florida here, after the state ordered it to dismiss a good number of its teachers as per their low VAM scores when this school year started. After realizing this also caused or contributed to a teacher shortage in the district, the district scrambled to hire Kelly Services contracted substitute teachers to replace them, after which the district also put administrators back into the classroom to help alleviate the bad situation turned worse.

In a recent post released by The Ledger, teachers from the same Polk County School District (size = 100K students) added much needed details and also voiced concerns about all of this in the article that author Madison Fantozzi titled “Polk teachers: We are more than value-added model scores.”

Throughout this piece Fantozzi covers the story of Elizabeth Keep, a teacher who was “plucked from” the middle school in which she taught for 13 years, after which she was involuntarily placed at a district high school “just days before she was to report back to work.” She was one of 35 teachers moved from five schools in need of reform as based on schools’ value-added scores, although this was clearly done with no real concern or regard of the disruption this would cause these teachers, not to mention the students on the exiting and receiving ends. Likewise, and according to Keep, “If you asked students what they need, they wouldn’t say a teacher with a high VAM score…They need consistency and stability.” Apparently not. In Keep’s case, she “went from being the second most experienced person in [her middle school’s English] department…where she was department chair and oversaw the gifted program, to a [new, and never before] 10th- and 11th-grade English teacher” at the new high school to which she was moved.

As background, when Polk County School District officials presented turnaround plans to the State Board of Education last July, school board members “were most critical of their inability to move ‘unsatisfactory’ teachers out of the schools and ‘effective’ teachers in.”  One board member, for example, expressed finding it “horrendous” that the district was “held hostage” by the extent to which the local union was protecting teachers from being moved as per their value-added scores. Referring to the union, and its interference in this “reform,” he accused the unions of “shackling” the districts and preventing its intended reforms. Note that the “effective” teachers who are to replace the “ineffective” ones can earn up to $7,500 in bonuses per year to help the “turnaround” the schools into which they enter.

Likewise, the state’s Commissioner of Education concurred saying that she also “wanted ‘unsatisfactory’ teachers out and ‘highly effective’ teachers in,” again, with effectiveness being defined by teachers’ value-added or lack thereof, even though (1) the teachers targeted only had one or two years of the three years of value-added data required by state statute, and even though (2) the district’s senior director of assessment, accountability and evaluation noted that, in line with a plethora of other research findings, teachers being evaluated using the state’s VAM have a 51% chance of changing their scores from one year to the next. This lack of reliability, as we know it, should outright prevent any such moves in that without some level of stability, valid inferences from which valid decisions are to be made cannot be drawn. It’s literally impossible.

Nonetheless, state board of education members “unanimously… threatened to take [all of the district’s poor performing] over or close them in 2017-18 if district officials [didn’t] do what [the Board said].” See also other tales of similar districts in the article available, again, here.

In Keep’s case, “her ‘unsatisfactory’ VAM score [that caused the district to move her, as] paired with her ‘highly effective’ in-class observations by her administrators brought her overall district evaluation to ‘effective’…[although she also notes that]…her VAM scores fluctuate because the state has created a moving target.” Regardless, Keep was notified “five days before teachers were due back to their assigned schools Aug. 8 [after which she was] told she had to report to a new school with a different start time that [also] disrupted her 13-year routine and family that shares one car.”

VAM-based chaos reigns, especially in Florida.