Our Approach to Adjusting Bell Times

  • As we thoroughly examine the ways to create more efficient school day start- and end-times for the 2018-19 school year, we face a daunting number. There are 1.8 octodecillian possible school start time combinations. That is, as a system, we could make the district's 125 schools start at any one of 1, 797, 010, 299, 914, 431, 210, 413, 179, 829, 509, 605, 039, 731, 475, 627, 537, 851, 106, 401 combinations. That is just under 3 times the estimated amount of grains of sand in the world.  


    Over the last year, we’ve worked to develop a process that enables us to address these issues. We go into depth on this process below.

Out Approach

Our Approach

  • 1) Comprehensively understand community start time preferences

    Last spring, we invited all BPS parents to take an online survey letting us know their preferences on when their school should start and their overall satisfaction with BPS transportation. Additionally, we also called several thousand parents to get their preferences. While we did not hear from every family, we heard from the parents of nearly 7,000 students and the average BPS school had 57 responses. Additionally, we heard from over 2,100 school based staff – including nearly 1,600 teachers.

    Because of the number of responses here, we can slice our responses in a number of ways – and we hope that you do too! We’ve posted the excel data for schools on our website.

    Two things jumped out. First, the common knowledge that people like start times from 8am-8:30am appears to be true. Generally speaking, parents gave those a higher score than start times at 7:30am or 9:30am.

     District Wide Bell Time Prefernces

    Second, there are parents within each school that have opposing preferences. Some parents highly prefer school starting at 7am. Some want school to start at 9:30am. Take the Murphy School in Dorchester, for example. As the graph below shows, at least one parent liked each bell time – and at least one parent hated each bell time!

    Murphy Bell Time Preference


    A recent survey, shown in the graph below, found that when picking a school 55% of parents said that school start and end times were very important.* However, that only made it the 13th most important option.

    Survey Results


    2) Develop a fast and reliable way to estimate costs

    While our parent survey was out in the field, we were working on the BPS Transportation Challenge. The Challenge had two goals:

    • Make our bus routes more efficient
    • Enable us to more efficiently balance our bell times

    Our winning team – the Quantum Team – came from MIT (you can read a bit more about them in WBUR and in the Wall Street Journal). We implemented part of their solution this year, which enabled us to use 50 fewer buses  – saving 20,000 pounds of CO2 emissions each school day so far this year, and nearly $5 million to reinvest back into schools.

    The Quantum solution can design our routes more quickly than we can manually. Whereas our system has historically taken ~3,000 hours to route our system, the Quantum solution can produce a robust estimate in 30 minutes. This enables us to look at a much broader range of scenarios.

    Because this is a computer model, we’re able to include the possibility of including a number of other models. It is possible to work to maximize happiness while minimizing costs – or to minimize the number of high school students starting before 8:00 am or minimize the number of elementary school students starting after 9:00 am. Whatever the scenario or the goal, we can work to adjust our model to reach it – while monitoring the inherent tradeoffs.


    3) Engage the community

    We know that there is no ‘right’ answer here. Depending on your preferences and priorities, you may reach a very different solution from someone else. We want to hear your preferences and priorities and engage honestly and genuinely as we rethink our priorities here.

    Over the next few weeks and months, we’ll be out in the community looking to hear from you. We encourage your thoughts and ideas. Feel free to email Charles Grandson, deputy chief of operations for BPS at cgrandson@bostonpublicschools.org, or submit your thoughts here in this anonymous comment box.


    4) Announce start times before the school choice process begins

    It is very important to us that finish this process in time to let our families know before the annual school choice process works. To accomplish this, we will be presenting our proposed plan to the Boston School Committee on November 15th. School Committee will vote on this proposed policy at their following meeting, December 6th. Bell times will be announced on December 7th in advance of school showcases on December 9th. 




    *Preliminary survey results from Boston Schools Fund / Mass Inc.