

Useobservations & invariance tests 

Message/Author 


Dear Dr. Muthen, I have two questions regarding the useobservations command. 1. I face some problems with specifying the useobservations command correctly if I want to use only a subset of observations based upon multiple variables. If I want to combine "AND" and "OR" commands here, is the following example correct (i.e., are the brackets correct and a must)? useobservations = variableA NE 10 AND variableB NE 1 AND variable C EQ 1 AND (variableD EQ 1 OR variableD EQ 2 variableD region EQ 4); 2. Imagine that I want to do invariance tests across 3 groups as defined by 3 different values on a specific variable although, in total, there are 5 different groups/values for this variable. Is it necessary to restrict the analysis with useobservations first to these 3 groups? Or is it enough to simply specify the 3 groups in the "grouping"? I highly appreciate all your efforts. Thanks in advance! 

Thuy Nguyen posted on Tuesday, January 23, 2018  5:32 pm



1. The statement is almost correct. You have a few missing OR keywords in the last expression. Is REGION a typo? The following is correct if we remove REGION: useobservations = variableA NE 10 AND variableB NE 1 AND variable C EQ 1 AND (variableD EQ 1 OR variableD EQ 2 OR variableD EQ 4); 2. You do not need to add a USEOBSERVATIONS statement. You will get a warning for those group values that are not mentioned in the GROUPING option similar to the one below: Data set contains unknown or missing values for GROUPING, PATTERN, COHORT, CLUSTER and/or STRATIFICATION variables. Number of cases with unknown or missing values: 585 You can ignore this warning. 

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