The Star Properties Concept Inventory (SPCI) is among the first instruments made available to assess student gains in a major section or "unit" of a traditional introductory astronomy course, in this case the unit on stars. This is in contrast to instruments for an entire course, such as the Astronomy Diagnostic Test or the Lunar Phases Concept Inventory that is for a single subject. One of the intended uses of the SPCI is for comparison of the effectiveness of different instructional methods. The following is a report on the results of a study in which the SPCI was used as a pretest and post test to compare gains in active and collaborative student-centered instruction using lecture tutorials to those in traditional instructor-centered instruction. (Contains 5 notes and 2 figures.)