Recent research suggests that the use of student search services is an effective part of a college's student marketing and recruitment strategy. What is not clear, however, is whether participating in a search service is an effective part of a student's college search strategy. To address this question, we exploit a recent change in the choice architecture that structures students' decision to participate in ACT's Educational Opportunity Service (EOS) in order to make a causal inference about the benefit to the student of opting into a search service. We hypothesized that students who had opted into EOS unintentionally sent scores to more colleges than students who opted out. Indeed, we found that unintentional opt-in was associated with an 8% increase in the odds of sending scores to any colleges, and for students who sent scores, unintentional EOS opt-in was associated with a 1.1 increase in the number of colleges to which scores were sent. Results of this study support the hypothesis that EOS opt-in may indeed be an effective part of a student's college search strategy.