Initial Thoughts on MIT Report on Proposed Assignment Plans
MIT has now released a report with a tremendous amount of detail on their simulation of the three proposed student assignment plans. There are three files. The main report is 51 pages. There is also a 27 page technical appendix and a 137 page graphical appendix. So to say there's a lot to digest here would be an understatement.
I've read through the main report and skimmed the other two. I doubt that many people will find the technical appendix useful as it is indeed quite technical. The main report and graphical appendix are more accessible, though still fairly complex. In particular, I would recommend to anyone reading the report that you read as much of the detail on what each measurement means and how it was calculated. A quick read could definitely leave you misinterpreting some of the data.
One thing that's important to know is that most of the measurements in the report are based on round 1 of 2012's K2 assignments. MIT looked at what would have happened last year if each of the new plans had been in effect. Kids who entered in later rounds are not included in the numbers. Also, the numbers for the current plan are also based on their simulation of 2012's K2 round 1 to create an apples-to-apples comparison. However, there is one difference between their simulations of the current and proposed plan. For the current plan, they use the current method of applying walk zone priority first. For the new plans they use the BPS proposal to change the assignment order to what they call a "compromise plan." It does not appear that this change has a large effect, but it probably provides some additional advantage to walk zone students.
One of the easiest things to look at is distance to school. This is clearly improved in all of the plans. In addition, the range of distances is much smaller in these new plans when looking at the 25th and 75th percentiles. That means that there won't be as much variance in distance traveled as there is now, but there will still be outliers who have to travel over five miles to school. The differences between the three proposed plans is small with a median distance of 1.12 to 1.19 miles compared to 1.87 for the current plan.
They also looked at bus coverage area. This is the geographic area around a school but outside of its walk zone where students could apply to that school and could potentially need to be bused. This is also significantly reduced for all plans, ranging from an average of 6.9 to 8.6 square miles when the ELL overlay is included. This compares to 24.5 square miles under the current plan.
Moving on to equity, there are several ways to look at this. MIT is using a measurement called Effective Access to Quality. They are using BPS's quality measurement which says that the top 50% of schools are quality schools, based on MCAS scores. They're defining access to quality as the chance a child has of getting into one of these schools, if the child chooses quality schools. This is an important distinction because not all parents are choosing quality schools based on this definition. In fact, MIT found that about 57% of of families are currently choosing a "quality" school as their first choice.
This is a reasonable way to look at this since it really doesn't make sense to say that a student who has quality schools on his or her list of choices, but chooses other schools first doesn't have access to quality schools. The numbers that BPS has already released on this show the access to quality for the child with the lowest chance of getting a quality school. In the current plan, this is 19.5% in round 1. Remember, that's not the typical student, it's the one with the worst chances. The new plans would increase this to 22.6% for 10 zone, 22.4% for Home-Based A, and 25.5% for Home-Based B. These aren't huge, but they are significant differences. The report also has a char that shows the full range of access and the 25th and 75th percentiles. I think these are more useful than looking at the worst case, as that could be an outlier. The 10 zone plan has a significantly higher range of access between the 25th and 75th percentiles than the current plan which means that by this measure it's less equitable. Home-Based plan A has a slightly smaller range and plan B has a still smaller range. Since Home-Based B also has the highest chance at the worst case I feel that it is the most equitable of the plans.
The report also looks at how well the plans perform as far as giving families access to their top choices. This can be thought of as a different way of looking at access to quality. Instead of using the BPS measure of quality, this uses parents' perception of quality as they choose schools. In some respects, this may be a better measurement as we know that the MCAS measurement is very limited and that each parent has his or her own definition of quality. On the other hand, some parents are inevitably making more informed choices than others, so this is still not a perfect measurement.
MIT looked at access to top choices in two ways. One is to look at access to the top menu choices. This is pretty straightforward. Knowing what each families available schools are and using the demand model to approximate how they will rank those choices, what are a family's chances of getting into one of their top three choices? The problem with this measure is that it doesn't consider whether the schools a family wants are even on the choice list in the first place. In fact, by simply reducing the number of choices you are almost guaranteed to increase access to families' top menu choices (once you get down to three choices per family, you will reach 100%). So MIT also looked at access to what they call a family's "Top Dream Choices." This is defined as the top schools the family would choose if they had access to all BPS schools. They then look at what chance the family would have of getting one of these schools in the various plans. This measure penalizes a plan that doesn't offer families the schools they want or lets them choose these schools but gives them little chance of getting in.
Under the Top Dream Choices measurement all of the new plans perform worse than the current plan. This is not surprising as they all offer families significantly fewer choices. In addition, the current plan is more equitable as it has a smaller range of access for different students under this measurement. There is very little difference among the three proposed plans under this measurement.
Consider this Part I of a series of posts on this report. There's a lot more here that I will try to cover in the next few days. The report contains maps to give an idea of geographic equity and break-downs based on race, ethnicity, and socioeconomics. Suffice to say that this is all quite complicated and will require careful consideration as we all try to understand how any of these new plans would affect our public schools and our city.