Using a sample of 908 eleventh grade science stream male and female students from similar socioeconomic area schools, variance based psychometric properties of three paper-and-pencil tests of logical thinking (Longeot test, Lawson's test TOFR, and Tobin and Capie's test TOLT) are investigated. A sub-sample of 212 students took the three tests in randomly allocated different sequential orders of presentation, while 696 students took only two tests. Alfa coefficients for each test separately and for the three tests combined together, concurrent validity coefficients, measures of item difficulty, item discrimination, item-criterion correlation, and 30-day stability coefficients are calculated. Considering the relative homogeneity of the sample, the reliability coefficients of the tests are judged satisfactory, but concurrent validity coefficients are quite low which implies incongruency in decisions made on the basis of the three tests. Need for estimating various psychometric parameters of alternative tests of logical thinking over different grade populations is emphasized.