I am very new to Mplus so I apologize if this is a silly question. I'm doing path analysis, have coded and account for missing data using SPSS. When I run my model in Mplus, my n size decreases significantly (more than half). I ran the model in SPSS (just doing regression analysis) and the n size was closer to what it was supposed to be. I'm doing secondary data analysis- n= 15,000 but when I run the model n= 6,000. Any ideas on why the n size decreases so much when I run the model in Mplus? Any suggestions for trouble shooting this issue? Thank you so much!