Reserve Design: Unintended Consequences and the Demise of Boston’s Walk Zones

School Assignment, April 2019

We show that in the pres­ence of admis­sions reserves, the effect of the prece­dence order (i.e., the order in which dif­fer­ent types of seats are filled) is com­pa­ra­ble to the effect of adjust­ing reserve sizes. Either low­er­ing the prece­dence of reserve seats at a school or increas­ing the school’s reserve size weak­ly increas­es reserve-group assign­ment at that school. Using data from Boston Public Schools, we show that reserve and prece­dence adjust­ments have sim­i­lar quan­ti­ta­tive effects. Transparency about these issues—in par­tic­u­lar, how prece­dence unin­ten­tion­al­ly under­mined intend­ed policy—led to the elim­i­na­tion of walk zone reserves in Boston’s pub­lic school match.