The main objectives of the study were: (1) To develop the Programmed Learning Material (PLM) on two chapters of Economics taught to Standard XI by following the Linear and Branching method. (2) To construct the Achievement tests on the content of the two chapters by following the standardization procedures. (3) To compare the effectiveness of the Linear and Branching type of PLM. (4) To compare the Achievement scores of the pupils having high and low Reading Ability; high and low Motivation; first and second or above birth order and high and low education of parents. (5) To assess the interaction effect of the various independent variables (mentioned above) on the Achievement scores of the pupils.  

The initial sample of 2452 pupils of Standard XI was selected randomly from 15 randomly selected schools of Ahmedabad city. Reading Ability Test (Trivedi and Patel), the adapted form of Smith’s N-Ach. Test (Patel and Dhanger) and a datasheet (to know their birth order and parents’ education) were administered on the pupils. After scoring, keeping in mind the levels of the independent variables, the final sample was shrunk to 1200 pupils. These were divided into three groups each consisting of 400 pupils.

Then the treatments i.e. Textual Material, Branching PLM and Linear PLM were assigned randomly to these groups. The BPLM and LPLM were developed for two units of the syllabus of Standard XI following the scientific procedure. These units were the Law of Demand’ and the Law of Supply’. 

After the material being read, the three groups were administered the Achievement tests on the two units, which were prepared scientifically following the steps of standardisation. The total of the two tests were taken as a complete score of Achievement for each pupil.

(1) The Linear PLM was found to be the most effective whereas the Textual material was least effective for Achievement. (2) The main effects of Reading Ability, Motivation, Birth Order and Parents’ Education were significant on Achievement in Economics. (3) The first order interactions between Treatment and Reading Ability; Treatment and Birth Order; Treatment and Parents’ Education were found to affect significantly the Achievement in Economics. (4) The Second order interactions among Treatment, Reading Ability and Birth Order; among Treatment, Motivation and Birth Order; among Reading Ability, Motivation and Birth Order; and among Parents’ Education, Motivation and Birth Order were significant on Achievement in Economics. (5) All independent variables more or less contributed equally to the Achievement in Economics of Standard XI pupils.