Introductory laboratory courses play an important role in student learning in introductory geoscience courses. In an attempt to quantify different effects on student learning, we evaluated the influence of six factors: situational interest, course format, course, lab topic, lab level of inquiry, and Teaching Assistant (TA). Data were collected from six introductory geoscience laboratory courses at five public research institutions for four semesters. Student learning was measured using pre- and post- course surveys with three content questions for each of six lab topics considered per course. Lab topics studied were selected by each course instructor and learning survey questions were aligned directly to the lab activities of each course. Unexpectedly, some labs were offered online during the study period, which is included as a potential learning factor (course format). Odds ratio analyses indicate that of all our factors, the topic of the lab activity, the TA lab instructor, and the course students are in, are strong predictors of student learning. Of the lab topics, there are higher odds of student learning for lab activities on Minerals, Earth's Interior, and Earthquakes. We do not propose that student interest, inquiry levels and course format are not important to student learning, but our data collection and analyses show they are not as important as lab topics and course factors in this dataset. These findings suggest that lab topics with lower odds ratios are prime opportunities for potential improvements to support student learning. To address the influence of courses, our further work will consider more nuanced analyses of factors related to individual courses such as individual lab activities at institutions and TA influences.