This article contains a description of concrete methods by means of which the characteristics of the so-called basic teaching material can be exactly evaluated. The starting point is the conception of basic teaching material created as early as the 1950s by O. Chlup. It is true that this conception was accepted by the Czechoslovak didactic science on the theoretical level, but no empirical research into basic teaching material has ever taken place. The article describes two approaches to an exact research into basic teaching material (on the basis of textbook material):
(1) The approach based on measuring the objective characteristics of the teaching material. In this approach it is possible to apply methods for analysing content characteristics of the teaching material (part 2.1.), especially: analyses of structurally logical relationships in the caching material, of semantic characteristics of the teaching material, of informative characteristics of the teaching material. In addition, methods for measuring communication parameters of the teaching material can be applied (part 2.2.), especially: analyses of comprehensibility, difficulty and quantity of the teaching material. Application of both these types of methods is illustrated by concrete examples using the material of Czech textbooks for elementary and secondary schools.
(2) The approach based on an expert evaluation of the characteristics of the teaching material. A description is given of methods of didactic texts evaluation by groups of experts and textbook users.
In conclusion, the author expresses the opinion that application of the abovementioned methods for an exact investigation of teaching material is no doubt demanding, but because of its practical importance due attention must be paid to it in didactic researches. In the near future the selection and evaluation of teaching material will be made by computers. Didactic researches must create a basis for these new tehnological methods by carrying out exact empirical and theoretical researches into the problems of creating and analysing teaching material.