The purpose of the study was to assess the degree to which a data-based intervention influenced preservice teachers' use of Mosston and Ahsworth's (2001) spectrum of teaching styles during peer teaching. Participants included two intact cohorts of preservice physical education teachers (PPETs) enrolled in a middle school physical education methods course at different times. Cohort 1 (n = 22) served as the control group and Cohort 2 (n = 29), a year later, served as the experimental group. PPETs in both cohorts were required to team-teach, in pairs or groups of threes, two lessons employing the Reciprocal, Guided Discovery, and Divergent Thinking styles. All the lessons were videotaped. The following documents resulted from the peer teaching: (a) Two lesson plans by each pair or group of PPETs (b) Two videotaped lessons by each pair or group of PPETs (c) Two sets of instructor feedback for each pair or group of PPETs, and (d) Two reflection papers by each PPET. In addition, Cohort 2 watched and coded videotapes of their first lessons using the Instrument for Identifying Teaching Styles (IFITS) prior to writing their first reflection papers. Document analysis and observation served as the main sources of data. The lesson plans, videotaped lessons, and reflection papers were analyzed using constant comparative analysis and analytic induction (Patton, 2002), while the IFITS data (inter-observer reliability = 95.24%) were analyzed using descriptive statistics. Results indicated that the intervention did: (a) Have an effect on the percentage of class time PPETs spent teaching in the Guided Discovery and the Divergent styles but not the Reciprocal style (b) Show PPETs in both groups spent most of their time employing the Practice style (though not a focus of their assignment) (c) Improve the quality of PPETs' reflections about their teaching (d) Help PPETs overcome some pedagogical difficulties. Mean percentage of class time PPETs in Cohort 2 employed the Guided Discovery and Divergent Thinking increased from 3.85% to 17.26% and from .00% to 10.62% respectively. That for the Reciprocal style increased, only slightly, from .00% to .88%. Alternatively, mean percentage of class time PPETs in Cohort 1 (control group) employed Guided Discovery increased slightly from 3.77% to 5.02%. However, this group did not employ the Divergent or Reciprocal styles during the pre- and post-intervention periods (.00%). Allowing PPETs to watch and code videotapes of their own teaching has the potential to improve their reflective and goal-setting skills.Keyword(s): college level issues, pre-service/student, professional preparation