This study assessed undergraduates' ability to identify independent and dependent variables in acid-base titration experiments. The researcher measured students' ability to identify the independent variable as an acid or base before and after a guided lab experiment. Students scored higher in identifying an acid as the independent variable after the lab. However, their ability to identify a base as independent decreased compared to an acid. Students also scored lower in describing the direct relationship between variables when the independent variable was a base instead of an acid. The results suggest students are more familiar with acids as independent variables in titration experiments.