The Thrill Of Success, The Agony Of Measurement

** Reprinted here in the Washington Post

The recent release of the latest New York State testing results created a little public relations coup for the controversial Success Academies charter chain, which operates over 20 schools in New York City, and is seeking to expand.

Shortly after the release of the data, the New York Post published a laudatory article noting that seven of the Success Academies had overall proficiency rates that were among the highest in the state, and arguing that the schools “live up to their name." The Daily News followed up by publishing an op-ed that compares the Success Academies' combined 94 percent math proficiency rate to the overall city rate of 35 percent, and uses that to argue that the chain should be allowed to expand because its students “aced the test” (this is not really what high proficiency rates mean, but fair enough).

On the one hand, this is great news, and a wonderfully impressive showing by these students. On the other, decidedly less sensational hand, it's also another example of the use of absolute performance indicators (e.g., proficiency rates) as measures of school rather than student performance, despite the fact that they are not particularly useful for the former purpose since, among other reasons, they do not account for where students start out upon entry to the school. I personally don't care whether Success Academy gets good or bad press. I do, however, believe that how one gauges effectiveness, test-based or otherwise, is important, even if one reaches the same conclusion using different measures.

Expectations For Student Performance Under NCLB Waivers

A recent story in the Chicago Tribune notes that Illinois’ NCLB waiver plan sets lower targets for certain student subgroups, including minority and low-income students. This, according to the article, means that “Illinois students of different backgrounds no longer will be held to the same standards," and goes on to quote advocates who are concerned that this amounts to lower expectations for traditionally lower-scoring groups of children.

The argument that expectations should not vary by student characteristics is, of course, valid and important. Nevertheless, as Chad Aldeman notes, the policy of setting different targets for different groups of students has been legally required since the enactment of NCLB, under which states must “give credit to lower-performing groups that demonstrate progress." This was supposed to ensure, albeit with exceedingly crude measures, that schools weren't punished due to the students they serve, and how far behind were those students upon entry into the schools.

I would take that a step further by adding two additional points. The first is quite obvious, and is mentioned briefly in the Tribune article, but too often is obscured in these kinds of conversations: Neither NCLB nor the waivers actually hold students to different standards. The cut scores above which students are deemed “proficient," somewhat arbitrary though they may be, do not vary by student subgroup, or by any other factor within a given state. All students are held to the same exact standard.

An Education Hearing I'd Like To See

At the end of February, the District of Columbia Council’s Education Committee held its annual hearing on the performance of the District’s Public Schools (DCPS). The hearing (full video is available here) lasted over four hours, and included discussion on a variety of topics, but there was, inevitably, a block of time devoted to the discussion of DCPS testing results (and these questions were the focus of the news coverage).

These exchanges between Council members and DCPS Chancellor Kaya Henderson focused particularly on the low-stakes Trial Urban District Assessment (TUDA).* Though it was all very constructive and not even remotely hostile, it’s fair to say that Ms. Henderson was grilled quite a bit (as is often the case at these kinds of hearings). Unfortunately, the arguments from both sides of the dais were fraught with the typical misinterpretations of TUDA, and I could not get past how tragic it is to see legislators question the superintendent of a large urban school district based on a misinterpretation of what the data mean - and to hear that superintendent respond based on the same flawed premises.

But what I really kept thinking -- as I have before in similar contexts -- was how effective Chancellor Henderson could have been in answering the Council’s questions had she chosen to interpret the data properly (and I still hold out hope that this will become the norm some day). So, let’s take a quick look at a few major arguments that were raised during the hearing, and how they might have been answered.

When Growth Isn't Really Growth, Part Two

Last year, we published a post that included a very simple graphical illustration of what changes in cross-sectional proficiency rates or scores actually tell us about schools’ test-based effectiveness (basically nothing).

In reality, year-to-year changes in cross-sectional average rates or scores may reflect "real" improvement, at least to some degree, but, especially when measured at the school- or grade-level, they tend to be mostly error/imprecision (e.g., changes in the composition of the samples taking the test, measurement error and serious issues with converting scores to rates using cutpoints). This is why changes in scores often conflict with more rigorous indicators that employ longitudinal data.

In the aforementioned post, however, I wanted to show what the changes meant even if most of these issues disappeared magicallyIn this one, I would like to extend this very simple illustration, as doing so will hopefully help shed a bit more light on the common (though mistaken) assumption that effective schools or policies should generate perpetual rate/score increases.

Estimated Versus Actual Days Of Learning In Charter School Studies

One of the purely presentational aspects that separates the new “generation” of CREDO charter school analyses from the old is that the more recent reports convert estimated effect sizes from standard deviations into a “days of learning” metric. You can find similar approaches in other reports and papers as well.

I am very supportive of efforts to make interpretation easier for those who aren’t accustomed to thinking in terms of standard deviations, so I like the basic motivation behind this. I do have concerns about this particular conversion -- specifically, that it overstates things a bit -- but I don’t want to get into that issue. If we just take CREDO’s “days of learning” conversion at face value, my primary, far more simple reaction to hearing that a given charter school sector's impact is equivalent to a given number of additional "days of learning" is to wonder: Does this charter sector actually offer additional “days of learning," in the form of longer school days and/or years?

This matters to me because I (and many others) have long advocated moving past the charter versus regular public school “horserace” and trying to figure out why some charters seem to do very well and others do not. Additional time is one of the more compelling observable possibilities, and while they're not perfectly comparable, it fits nicely with the "days of learning" expression of effect sizes. Take New York City charter schools, for example.

Select Your Conclusions, Apply Data

The recent release of the National Assessment of Educational Progress (NAEP) and the companion Trial Urban District Assessment (TUDA) was predictably exploited by advocates to argue for their policy preferences. This is a blatant misuse of the data for many reasons that I have discussed here many times before, and I will not repeat them.

I do, however, want to very quickly illustrate the emptiness of this pseudo-empirical approach – finding cross-sectional cohort increases in states/districts that have recently acted policies you support, and then using the increases as evidence that the policies “work." For example, the recent TUDA results for the District of Columbia Public Schools (DCPS), where scores increased in all four grade/subject combinations, were immediately seized upon supporters of the reforms that have been enacted by DCPS as clear-cut evidence of the policy triumph. The celebrators included the usual advocates, but also DCPS Chancellor Kaya Henderson and the U.S. Secretary of Education Arne Duncan (there was even a brief mention by President Obama in his State of The Union speech).

My immediate reaction to this bad evidence was simple (though perhaps slightly juvenile) – find a district that had similar results under a different policy environment. It was, as usual, pretty easy: Los Angeles Unified School District (LAUSD).

Is Selective Admission A School Improvement Plan?

The Washington Post reports that parents and alumni of D.C.’s Dunbar High School have quietly been putting together a proposal to revitalize what the article calls "one of the District's worst performing schools."

Those behind the proposal are not ready to speak about it publicly, and details are still very thin, but the Post article reports that it calls for greater flexibility in hiring, spending and other core policies. Moreover, the core of the plan – or at least its most drastic element - is to make Dunbar a selective high school, to which students must apply and be accepted, presumably based on testing results and other performance indicators (the story characterizes the proposal as a whole with the term “autonomy”). I will offer no opinion as to whether this conversion, if it is indeed submitted to the District for consideration, is a good idea. That will be up to administrators, teachers, parents, and other stakeholders.

I am, however, a bit struck by two interrelated aspects of this story. The first is the unquestioned characterization of Dunbar as a “low performing” or “struggling” school. This fateful label appears to be based mostly on the school’s proficiency rates, which are indeed dismally low – 20 percent in math and 29 percent in reading.

A Quick Look At The DC Charter School Rating System

Having taken a look at several states’ school rating systems  (see our posts on the systems in IN, OH, FL and CO), I thought it might be interesting to examine a system used by a group of charter schools – starting with the system used by charters in the District of Columbia. This is the third year the DC charter school board has released the ratings.

For elementary and middle schools (upon which I will focus in this post*), the DC Performance Management Framework (PMF) is a weighted index composed of: 40 percent absolute performance; 40 percent growth; and 20 percent what they call “leading indicators” (a more detailed description of this formula can be found in the second footnote).** The index scores are then sorted into one of three tiers, with Tier 1 being the highest, and Tier 3 the lowest.

So, these particular ratings weight absolute performance – i.e., how highly students score on tests – a bit less heavily than do most states that have devised their own systems, and they grant slightly more importance to growth and alternative measures. We might therefore expect to find a somewhat weaker relationship between PMF scores and student characteristics such as free/reduced price lunch eligibility (FRL), as these charters are judged less predominantly on the students they serve. Let’s take a quick look.

Are There Low Performing Schools With High Performing Students?

I write often (probably too often) about the difference between measures of school performance and student performance, usually in the context of school rating systems. The basic idea is that schools cannot control the students they serve, and so absolute performance measures, such as proficiency rates, are telling you more about the students a school or district serves than how effective it is in improving outcomes (which is better-captured by growth-oriented indicators).

Recently, I was asked a simple question: Can a school with very high absolute performance levels ever actually be considered a “bad school?"

This is a good question.

Under The Hood Of School Rating Systems

Recent events in Indiana and Florida have resulted in a great deal of attention to the new school rating systems that over 25 states are using to evaluate the performance of schools, often attaching high-stakes consequences and rewards to the results. We have published reviews of several states' systems here over the past couple of years (see our posts on the systems in Florida, Indiana, Colorado, New York City and Ohio, for example).

Virtually all of these systems rely heavily, if not entirely, on standardized test results, most commonly by combining two general types of test-based measures: absolute performance (or status) measures, or how highly students score on tests (e.g., proficiency rates); and growth measures, or how quickly students make progress (e.g., value-added scores). As discussed in previous posts, absolute performance measures are best seen as gauges of student performance, since they can’t account for the fact that students enter the schooling system at vastly different levels, whereas growth-oriented indicators can be viewed as more appropriate in attempts to gauge school performance per se, as they seek (albeit imperfectly) to control for students’ starting points (and other characteristics that are known to influence achievement levels) in order to isolate the impact of schools on testing performance.*

One interesting aspect of this distinction, which we have not discussed thoroughly here, is the idea/possibility that these two measures are “in conflict." Let me explain what I mean by that.