The concept of 'algorithm efficiency' in the high school curriculum

Algorithms and the efficiency of algorithms are basic concepts to every computer science (CS) curriculum (ACM Computing Curricula, 2001; Tucker, et al., 1993; Merrit, 1993). A new CS curriculum is being implemented in Israeli high schools which includes all the basic elements of traditional CS programs. At its core are algorithms, algorithmic thinking and the efficiency of algorithms which are included in the first two units studied (Gal-Ezer et al., 1995). Initial observations of the implementation of the program, interviews with teachers and students, and examination of students' achievements, confirmed our assumption that efficiency is a difficult concept to conceive, and motivated our research.