As first reported [1] by the New York Times, the New York City Department of Education released a dataset [2] this past Sunday, which lists the number of potential teacher layoffs that would occur in each school absent a budget infusion.

Layoffs are a terrible thing for schools and students, and this list is sobering. But the primary impetus for releasing for this dataset appears to be the city’s ongoing push [3] to end so-called seniority-based layoffs, and its support for seniority-ending legislation [4] that is now making its way through the state legislature. One of the big talking points on this issue has always been that layoffs that take experience into account would hurt high-poverty schools the most, because these schools tend to have the least experienced teachers [5]. As I discussed in a prior post [6], Michelle Rhee is making this argument everywhere she goes, and it was one of the primary themes in a new report [7] by the New Teacher Project (released last week). Although I have not heard city officials use the argument since the database was released over the weekend, similar assertions have very recently been made by Mayor Bloomberg [8], former Chancellor Joel Klein [9], and current Chancellor Cathie Black [10].

I find all this a bit curious, given that the best research on the topic finds that the argument is untrue (including a study of New York City [11], and a statewide analysis of Washington [12] [also here [13]]). Now, it is at least possible that, if layoffs were conducted strictly on the basis of seniority, higher-poverty schools could end up bearing the brunt of dismissals. This is almost never the case, however – layoffs in almost every district proceed based on a variety of criteria, among which seniority is only one (albeit often the most important).

It is fortuitous, then, that the city’s dataset provides an opportunity to test the claim that the “worst-case scenario” – over 4,500 layoffs using current New York City procedures – would hurt high-poverty schools the most. Let’s take a look.

I merged the city’s layoff dataset (which provides the percent of each school’s teachers that would be fired if all the layoffs proceed) with the city’s dataset [14] on school poverty rates (2009-10). A bunch of schools on the layoff list were missing from the poverty dataset (many opened this year), so I gathered poverty rates manually for as many of these schools as I could (the rest are excluded).

In the scatterplot below, each blue dot represents a school. The x-axis is percent of students in poverty (free/reduced lunch), and the y-axis is the percent of the school’s teachers laid off.   There is some bunching towards the right because, of course, most of the city’s schools have high poverty rates.  The red line in the middle is the fitted linear relationship between these two variables.

[15]

Layoffs appear rather dispersed between schools, while the correlation coefficient is miniscule, and not statistically significant at any level (see the figure’s stub). This is also evident in the red line, which is basically flat. In short, based on this quick analysis (as well as previous research on NYC layoffs), there seems to be little discernible relationship between school-level poverty and the percent of teachers who would be laid off.

(You may notice several schools [around 50, actually] clustered at the 60 percent poverty level. Most of them are new, and this may be how the city codes some schools' poverty rates before official enrollment figures are available. Removing these schools does not alter the results.)

Just to give an easier visual of this relationship (or lack thereof), the graph below presents the average layoff (percent of teachers) by school poverty, with schools divided in poverty quartiles.

[16]

Once again, the graph indicates that the effect of the layoffs, at least in terms of their incidence, is fairly evenly dispersed between higher- and lower-poverty schools.

These results reflect the fact that so-called “last in, first out” policies do not actually proceed in that manner. It might also, perhaps, reflect a weaker relationship between teacher experience and school poverty in New York City than is typically found elsewhere.

In any case, those making the argument that seniority-based layoffs “hurt poor children” should stop. There is no evidence for this claim beyond a couple of simplistic analyses [17] that assume – incorrectly – that layoffs are based strictly on years of service. (For the record, the above-mentioned New Teacher Project report did cite the Washington and NYC studies in their discussion of the relationship between layoffs and value-added scores, but ignored these papers in their section on differential impacts by poverty.)

The available evidence – including that from a massive projected layoff in the largest school district in the nation – finds otherwise. The irrefutable fact about this situation: Layoffs hurt all children

Personally, I support the idea of finding a better way to conduct the inherently awful practice of mass teacher firings. But let’s debate the alternatives with accurate information [18], and stop evoking, without clear evidence, society’s concern for the wellbeing of poor kids in order to advance policy agendas. In the long run, it does nothing to help the cause.