Problems with single interest scales: Implications of the general factor

The presence of the general factor in interest and self-efficacy assessment and its meaning are reviewed. The general factor is found in all interest and self-efficacy assessment and has been viewed as (a) a nuisance factor with little effect on assessment, (b) a variable having substantive meaning and thus worthy of including in interpretation, and (c) as systematic bias that distorts the interpretation of the meaning of assessments. The premise of this article is that each interpretation is correct but only depending upon the context of the assessment. The main implication is that narrow single content interest scales are very subject to contaminating effects of the general factor making interpretation very difficult. Methods of correcting this contamination are presented.