Content validation of Texas State-Adopted life, earth, physical, and biological science textbooks

Abstract

Passage of Texas House Bill 246 in 1981 has led to massive restructuring of the Texas educational system with the upgrading of the quality of textbooks an important part of the revisions. The purpose of this study was to determine whether or not the Texas State-Adopted science textbooks contained concepts, scientific attitudes, and process skills that were identified by Gibbons (1976) as minimum competencies for high school graduates to attain to be considered scientifically literate. The sample of textbooks examined was narrowed to the 25 textbooks under current adoption used in life science, earth science, physical science, introductory biology, and biology since it was assumed that most secondary students completed their last science course by grade ten. An evaluation instrument was developed along with a list of rules that was abided by all investigators when examining the textbooks. Five secondary science student teachers reviewed randomly selected chapters from the sample population of textbooks. Results indicated high inter-rater reliability. A total of 11,784 pages of narration were examined for concepts: 52 life science, 35 earth science, 41 physical science, and an additional 20 ecology. Concepts were coded as either defined, partially defined, explained, or example. The scientific attitudes and process skills were coded as present or not present. Based on the findings of this study, it is probable that the life, earth, physical, introductory biology, and biology students in the State of Texas are being exposed, to varying degrees, to concepts, scientific attitudes, and process skills necessary for scientific literacy. There was a significant difference in the presentations of the concepts. Very few concepts were defined or partially defined in the textbooks. The findings suggested that students had to learn concepts by understanding the explanations and examples and, through inductive reasoning, formulate the concepts in their minds. Scientific attitudes were sparse and mainly found in the chapter devoted to the scientific method. Process skills were abundant; however, some of the lab activities were ambiguously written so it was difficult to determine what process skills were being used.