MacCallum et al. (1996, 1997, 2006) and Kim (2005) propose methods to calculate the required sample size (given a desired power) or the achieved power (given a sample size) to assess the fit of structural equation models based upon different fit indices (e.g. RMSEA or AGFI). The code on this page implements these routines in R and SPSS.

**Instructions**: Choose the calculation of interest below, fill in the necessary information and press the download button. To run the code, copy and paste it in your R or SPSS syntax window on your computer.

**Calculate required sample size**

**Note:**

Apparently Preacher and Coffman (2006) have already published similar R routines a while ago. You can run their code online, without having to install R on your computer. Check it out.

Some of these routines are also provided in the semTools package in R.

Additionally Friendly (2000) wrote a SAS Macro to conduct these power estimations.

## Literature

- Friendly, M. (2000, June).
*The csmpower macro - Power estimation for Covariance Structure Models*[Computer software]. Available from http://www.math.yorku.ca/SCS/sasmac/csmpower.html (2008-08-30). - Kim, K. H. (2005). The Relation Among Fit Indexes, Power, and Sample Size in Structural Equation Modeling.
*Structural Equation Modeling, 12*, 368-390. doi: 10.1207/s15328007sem1203_2. - MacCallum, R. C., Browne, M. W., & Cai, L. (2006). Testing differences between nested covariance structure models: Power analysis and null hypotheses.
*Psychological Methods, 11*, 19-35. doi: 10.1037/1082-989X.11.1.19. - MacCallum, R. C., Browne, M. W., & Sugawara, H. M. (1996). Power analysis and determination of sample size for covariance structure modeling.
*Psychological Methods, 1*, 130-149. doi: 10.1037/1082-989X.1.2.130. - MacCallum, R. C. & Hong, S. (1997). Power Analysis in Covariance Structure Modeling Using GFI and AGFI.
*Multivariate Behavioral Research, 32*, 193-210. doi: 10.1207/s15327906mbr3202_5 . - Preacher, K. J. & Coffman, D. L. (2006, May).
*Computing power and minimum sample size for RMSEA*[Computer software]. Available from http://www.quantpsy.org (2012-03-13).