2013 Journal of Microbiology & Biology Education 

Brownell, S., Kloser, M., Fukami, T., & Shavelson, R. (2013). Context Matters: Volunteer Bias, Small Sample Size, and the Value of Comparison Groups in the Assessment of Research-Based Undergraduate Introductory Biology Lab Courses. Journal of Microbiology & Biology Education : JMBE, 14(2), 176–182.