KM (A23, A24) is a measure of general reasoning, as operationally defined in the Educational Testing Service repertory. KM submits problems in a visual form, giving short verbal instructions. The arithmetic calculations are very easy and reduced to a minimum, so that numerical ability minimally interferes with reasoning ability. The items are arranged in four subtests giving rules increasing in number and complexity from the first to the fourth subtest, so that the reasoning process depends on attention and concentration as well as on finding an efficient solution strategy and making simple calculations.
Minimizing the arithmetic component is important when the examinees' educational level is low, and including a certain amount of complexity is relevant to generalizability to normal life situations.
General reasoning, measured by tests similar to KM, is regarded by the international scientific literature as positively correlated to high level staff performances.
A basic study on reliability and validity has been conducted on an Italian sample of 488 students, aged 17 to 19.

Reliability
A reliability value alfa = 0,87, calculated on the sample above, shows satisfactory homogeneity.

Correlation with other tests
KM scores have been correlated with scores from other cognitive tests in the guidance "battery" used by L. Boncori. The highest value (r = 0,41) is between KM and the numerical ability test NPQR-N , by L. Boncori, examining mathematical competence at the 8th grade level. Next higher (r = 0,33) is the correlation between KM and Otis Quick-scoring Gamma, a well known general intelligence test, mainly verbal. Correlation with a spatial reasoning (visualisation test), L-S (a reduced form of Kaleidoscope: see below) is lower (r = 0,23), but statistically significant (p < 0,01). As intercorrelations with the other cognitive test in the battery are significant, but low (from 5% to 17% of variance in common), it can be affirmed that KM adds new and independent information to the other tests in the battery.