Scoring in creativity research has been a central problem since creativity became an important issue in psychology and education in the 1950s. The current study examined the psychometric properties of 27 creativity indices derived from summed and averaged scores using 15 scoring methods. Participants included 2802 middle-school students. Data included students' scores on the Creative Scientific Ability Test (C-SAT). The following summed and averaged indices were included in the analysis: fluency, flexibility, creativity quotient, traditional creativity index, originality indices, 26 teachers' ratings of creativity and appropriateness, and additive and multiplicative indices of originality and appropriateness. Results showed that most summed indices were slightly or largely right-skewed and displayed leptokurtic distributions. Averaged indices showed less skewness with mesocurtic, platycurtic, and leptokurtic distributions. Summed scores had higher variance and reliability than did the averaged scores. Fluency contamination was evident on all the summed indices, with much higher contamination on flexibility and percentile-ranking-based originality. Interitem correlations between the indices are compared and contrasted using the equal odds baseline, dual pathway, and the trade-off model.