A technical analysis was made of the Assumed Similarity instrument used to measure team effectiveness of student surveyor teams. When each item of 5 clusters was considered separately, the reliabilities for ASo, ASp, and ASn were 0.93, 0.83, and 0.95, respectively. The internal consistency of separate clusters was low, and little intercorrelation existed between clusters. ASo and ASp were so highly correlated that separate treatment was not considered advisable. The ASp score was not considered reliable and partly independent of ASn and ASo. The ASo score as determined from differences on items within a cluster correlated highly with ASo's of other clusters, which indicated that assumed similarity was a general attitude essentially independent of the content of test items.