just to be sure I am loading my data sets correctly: 1) I used the command for data sets with headers: read.csv("outdata1.csv", header = TRUE) This resulted in my entire data set with headers being listed 2) I performed the same "read" function for each of the subsequent 4 data sets....after trial and error, I determined that they must be loaded individually... but after each read, each data set was displayed. 3) Finally, after all 5 "read" functions were performed, I was able to go back and perform diagnostics on any/all..ie..sim(), summary(), etc..... This is what makes me believe I loaded them properly. Thanks again. Mike ** Confidentiality Notice: This e-mail and any files transmitted with it are confidential to the extent permitted by law and intended solely for the use of the individual or entity to whom they are addressed. If you have received this e-mail in error please notify the originator of the message and destroy all copies. **