Chicago Public Schools (CPS) offers many options when it comes to high school enrollment. In fact, since the 2015-16 school year, about three out of every four incoming ninth-graders have chosen to attend a high school other than their assigned neighborhood school. Despite the widespread engagement in school choice, the high school application process was complicated. In an effort to simplify and streamline the process, the Chicago Board of Education voted on April 2017 to adopt a common application across all high school choice programs for incoming ninth-grade students with one deadline and a single best offer. The district expected that this common application would make the process simpler, more transparent, and more equitable for students and families. At the time when Chicago passed this measure, similar systems had already been approved and were in use in a number of other urban districts. Beginning in fall 2017, all high school program applications were moved to an online platform known as GoCPS. This new application system eliminated the need to apply school-by-school and program-by-program. In addition, all high school programs had a common deadline for applications and acceptances of offers. Importantly, the selection system alleviated the problem of some students accepting multiple offers to competitive programs while others remained on multiple waitlists with no offers. This report analyzes the first year of GoCPS implementation for students who enrolled in ninth grade in the fall of 2018. [Funding provided by the Consortium Investor Council.]