In vivo experiment

An in vivo experiment is a laboratory-style multi-condition experiment conducted in the classroom. Typically, the conditions manipulate a small but crucial, well-defined instructional variable, as opposed to a whole curriculum.

In the PSLC, which uses tutoring systems to monitor students' progress through the year, there are typically two types of in vivo experiments (to make this easier to follow, assume that there are just two conditions in the experiment, called the experimental and control conditions):

• The tutoring system is modified to implement the manipulation. Students assigned to the experimental condition do their work on the modified system; Students assigned to the control condition use the unmodified tutoring system. See Post-practice reflection (Katz) for an example.

• For a limited time, e.g., a one-hour classroom period or a two-hour lab period, the control students do one activity and the experimental students do another. The control activity typically is not one that students do during that period, but is nonetheless a common part of their normal instruction. For instance, they may watch a video of some problems being solved by their instructor. The tutoring system may or may not be involved with these activities. See Hausmann Study for an example.

Regardless of the experimental method used in an in vivo experiment, the tutoring systems record log data that are used to evaluate the effects of the manipulation.