To summarize knowledge on the effects of grouping and tracking in secondary schools, this synthesis uses ethnographic research to interpret the findings of survey analyses, and uses survey studies to assess the causal implications and degree to which ethnographic findings can be generalized. Survey studies consistently report that academic-track students are more likely to attend college and attain more schooling overall. However, no consensus exists about the effects of tracking on achievement or on student attitudes. The ethnographic literature reveals consistent track differences in students' academic experiences. High-track classes cover more complex material more quickly, exposing students to more high-status knowledge. Existing evidence does not show whether tracking actually causes polarization of students into pro- and anti-school factions, or whether this polarization results from pre-existing differences among students. Combining the survey and ethnography findings, the balance of the evidence suggests that grouping and tracking do affect achievement, despite the inconsistencies in survey analyses. A 73-item reference list is appended. (JD)