Plotting power curves for RMSEA
Alexander M. Schoemann (University of Kansas)
Kristopher J. Preacher (Vanderbilt University)
Donna L. Coffman (Pennsylvania State University)
This web utility may be cited in APA style in the following manner:
Schoemann, A. M., Preacher, K. J., & Coffman, D. L. (2010, April). Plotting power curves for RMSEA [Computer software]. Available from http://quantpsy.org/.
If the Rweb server is not working
The code generated by this utility can be pasted directly into an R console window. R (a free, opensource statistical computing environment) may be obtained here: http://cran.rproject.org/.
The purpose of this page, and how to use it
This web page generates R code that can create a plot of power for RMSEA against a range of sample sizes. The plot places sample size on the horizontal axis and power on the vertical axis. The user should indicate the lower and upper values for sample size and the sample size between each estimate ("step size") We strongly urge the user to read the sources below (see References) before proceeding. We have another calculator for conducting power analyses here.
Note: smaller values of "step size" will lead to more precise plots. However, smaller step sizes means a longer run time using Rweb.
When you are finished, click the button labeled "Submit above to Rweb" to compute the desired value. Alternatively, the R syntax may be copied and pasted into a command window of any PC installation of R.
Create a Plot for Power and Sample Size for RMSEA

MacCallum, R. C., Browne, M. W., & Cai, L. (2006). Testing differences between nested covariance structure models: Power analysis and null hypotheses. Psychological Methods, 11, 1935.
MacCallum, R. C., Browne, M. W., & Sugawara, H. M. (1996). Power analysis and determination of sample size for covariance structure modeling. Psychological Methods, 1, 130149.
MacCallum, R. C., Lee, T., & Browne, M. W. (2010). The issue of isopower in power analysis for tests of structural equation models. Structural Equation Modeling, 17, 2341.
Preacher, K. J., Cai, L., & MacCallum, R. C. (2007). Alternatives to traditional model comparison strategies for covariance structure models. In T. D. Little, J. A. Bovaird, & N. A. Card (Eds.), Modeling contextual effects in longitudinal studies (pp. 3362). Mahwah, NJ: Lawrence Erlbaum Associates.
Steiger, J. H. (1998). A note on multiple sample extensions of the RMSEA fit index. Structural Equation Modeling, 5, 411419.
Steiger, J. H., & Lind, J. C. (1980, June). Statistically based tests for the number of factors. Paper presented at the annual meeting of the Psychometric Society, Iowa City, IA.
Original version posted April, 2010.