One Florida District Kisses VAMs Goodbye

I recently wrote about how, in Louisiana, the state is reverting back to its value-added model (VAM)-based teacher accountability system after its four year hiatus (see here). The post titled “Much of the Same in Louisiana” likely did not come as a surprise to teachers there in that the state (like most other states in the sunbelt, excluding California) have a common and also perpetual infatuation with such systems, whether they be based on student-level or teacher-level accountability.

Well, at least one school district in Florida is kissing the state’s six-year infatuation with its VAM-based teacher accountability system goodbye. I could have invoked a much more colorful metaphor here, but let’s just go with something along the lines of a sophomoric love affair.

According to a recent article in the Tampa Bay Times (see here), “[u]sing new authority from the [state] Legislature, the Citrus County School Board became the first in the state to stop using VAM, citing its unfairness and opaqueness…[with this]…decision…expected to prompt other boards to action.”

That’s all the article has to offer on the topic, but let’s all hope others, in Florida and beyond, do follow.

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 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.


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

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.

A “Next Generation” Vision for School, Teacher, and Student Accountability

Within a series of prior posts (see, for example, here and here), I have written about what the Every Student Succeeds Act (ESSA), passed in December of 2015, means for the U.S., or more specifically states’ school and teacher evaluation systems as per the federal government’s prior mandates requiring their use of growth and value-added models (VAMs).

Related, states were recently (this past May) required to submit to the federal government their revised school and teacher evaluation plans, post ESSA, given how they have changed, or not. While I have a doctoral student currently gathering updated teacher evaluation data, state-by-state, and our preliminary findings indicate that “things” have not (yet) changed much post ESSA, at least at the teacher level of focus in this study and except for in a few states (e.g., Connecticut, Oklahoma), states still have the liberties to change that which they do on both ends (i.e., school and teacher accountability).

Recently, a colleague recently shared with me a study titled “Next Generation Accountability: A Vision for School Improvement Under ESSA” that warrants coverage here, in hopes that states are still “out there” trying to reform their school and teacher evaluation systems, of course, for the better. While the document was drafted by folks coming from the aforementioned state of Oklahoma, who are also affiliated with the Learning Policy Institute, it is important to note that the document was also vetted by some “heavy hitters” in this line of research including, but not limited to, David C. Berliner (Arizona State University), Peter W. Cookson Jr. (American Institutes for Research (AIR)), Linda Darling-Hammond (Stanford University), and William A. Firestone (Rutgers University).

As per ESSA, states are to have increased opportunities “to develop innovative strategies for advancing equity, measuring success, and developing cycles of continuous improvement” while using “multiple measures to assess school and student performance” (p. iii). Likewise, the authors of this report state that “A broader spectrum of indicators,
going well beyond a summary of annual test performance, seems necessary to account transparently for performance and assign responsibility for improvement.”

Here are some of their more specific recommendations that I found of value for blog followers:

  • The continued use of a single composite indicator to reduce and then sort teachers or schools by their overall effectiveness or performance (e.g., using teacher “effectiveness” categories or school A–F letter grades) is myopic, to say the least. This is because doing this (a) misses all that truly “matters,” including  multidimensional concepts and (non)cognitive competencies we want students to know and to be able to do, not captured by large-scale tests; and (b) inhibits the usefulness of what may be informative, stand-alone data (i.e., as taken from “multiple measures” individually) once these data are reduced and then collapsed so that they can be used for hierarchical categorizations and rankings. This also (c) very much trivializes the multiple causes of low achievement, also of importance and in much greater need of attention.
  • Accordingly, “Next Generation” accountability systems should include “a broad palette of functionally significant indicators to replace [such] single composite indicators [as this] will likely be regarded as informational rather than controlling, thereby motivating stakeholders to action” (p. ix). Stakeholders should be defined in the following terms…
  • “Next Generation” accountability systems should incorporate principles of “shared accountability,” whereby educational responsibility and accountability should be “distributed across system components and not foisted upon any one group of actors or stakeholders” (p. ix). “[E]xerting pressure on stakeholders who do not have direct control over [complex educational] elements is inappropriate and worse, harmful” (p. ix). Accordingly, the goal of “shared accountability” is to “create an accountability environment in which all participants [including governmental organizations] recognize their obligations and commitments in relation to each other” (p. ix) and their collective educational goals.
  • To facilitate this, “Next Generation” information systems should be designed and implemented in order to service the “dual reporting needs of compliance with federal mandates and the particular improvement needs of a state’s schools,” while also addressing “the different information needs of state, district, school site
    leadership, teachers, and parents” (p. ix). Data may include, at minimum, data on school resources, processes, outcomes, and other nuanced indicators, and this information must be made transparent and accessible in order for all types of data users to be responsive, holistically and individually (e.g, at school or classroom levels). The formative functions of such “Next Generation” informational systems, accordingly, take priority, at least for initial terms, until informational data can be used to, with priority, “identify and transform schools in catastrophic failure” (p. ix).
  • Related, all test- or other educational measurement-related components of states’ “Next Generation” statutes and policies should adhere to the Standards for Educational and Psychological Testing, and more specifically their definitions of reliability, validity, bias, fairness, and the like. Statutes and policies should also be written “in the least restrictive and prescriptive terms possible to allow for [continous] corrective action and improvement” (p. x).
  • Finally, “Next Generation” accountability systems should adhere to the following five essentials: “(a) state, district, and school leaders must create a system-wide culture grounded in “learning to improve;” (b) learning to improve using [the aforementioned informational systems also] necessitates the [overall] development of [students’] strong pedagogical data-literacy skills; (c) resources in addition to funding—including time, access to expertise, and collaborative opportunities—should be prioritized for sustaining these ongoing improvement efforts; (d) there must be a coherent structure of state-level support for learning to improve, including the development of a strong Longitudinal Data System (LDS) infrastructure; and (e) educator labor market policy in some states may need adjustment to support the above elements” (p. x).

To read more, please access the full report here.

In sum, “Next Generation” accountability systems aim at “a loftier goal—universal college and career readiness—a goal that current accountability systems were not designed to achieve. To reach this higher level, next generation accountability must embrace a wider vision, distribute trustworthy performance information, and build support infrastructure, while eliciting the assent, support, and enthusiasm of citizens and educators” (p. vii).

As briefly noted prior, “a few states have been working to put more supportive, humane accountability systems in place, but others remain stuck in a compliance mindset that undermines their ability to design effective accountability systems” (p. vii). Perhaps (or perhaps likely) this is because for the past decade or so states invested so much time, effort, and money to “reforming” their prior teacher evaluations systems as formerly required by the federal government. This included investments in states’ growth models of VAMs, onto which many/most states seem to be holding firm.

Hence, while it seems that the residual effects of the federal governments’ former efforts are still dominating states’ actions with regards to educational accountability, hopefully some states can at least begin to lead the way to what will likely yield the educational reform…still desired…