Orthogonal array testing

Orthogonal fields are tables that are used in the statistical design of experiments for creation of test plans.

Application

The simplest and most commonly used orthogonal fields contain rows and columns. In each table field is a plus or a minus. Each of the columns can be a trying factor to be assigned. Plus and minus stand for the two studied levels of the factor (example: temperature factor, " " then stands for the high temperature value, "- " for the low ). The lines correspond to the experimental runs and pretend each of the factors must be placed in the test run in question on which of its two stages.

Sometimes, instead of the coding of the - and and numbers (1, 2 or three factor levels such as -, 0, or 1, 2, 3).

Orthogonal fields is of central importance in the Taguchi method.

Mathematical Background

Orthogonal fields are arranged so that the main effects of the tested factors are not mixed together. The reason is that the scalar product of any two columns is always 0, which are the plus and minus signs in the column pairs so always evenly distributed and balanced with each other.

Orthogonal fields have short names such as, ,, etc. The stands for Latin square.