This paper describes how one university mathematics department was able to improve student success in Calculus I by requiring a co-requisite lab for certain groups of students. The groups of students required to take the co-requisite lab were identified by analyzing student data, including Math ACT scores, ACT Compass Trigonometry scores, and grades in Pre-Calculus. Following the creation of the required lab, we collected the same data on the lab students as we had on similar students enrolled in Calculus I prior to the creation of the lab. The data were analyzed comparing the grades of students who had taken the co-requisite lab with the grades of similar students that had taken Calculus I prior to the creation of the lab. Our observations indicate that there is an improvement in the pass rate (grade of C or better) in Calculus I for a certain group of lab students.