The second task is to check the data for skip patterns. To do this, you will use the:
Check the codebook to determine if a skip pattern affects the variables in your analysis. See the Locate Variables module Task 1 for more information on how to locate background information on variables in the documentation.
After you have used the codebook to discover if a skip pattern affects variables in your analysis, you will use cross tabulations obtained by the SAS proc freq procedure to determine the presence of skip patterns.
Statements | Explanation |
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data =demo_BP1; |
Use the proc freq procedure to determine the frequency of each value of the variables listed. |
where ridstatr=2 and ridageyr>=20; | Use the where statement to select participants who were interviewed and examined in the MEC and who were age 20 years and older. |
table BPQ020 BPQ030 BPQ050a BPQ020*(BPQ030 BPQ050a)/ list missing ; title 'Check skip pattern for BP questionnaire' ; ; |
Use the table statement to list the variables to be included in the output frequency table and the cross tabulation frequency table for the skip patterns. Note that a star (*) indicates that a crosstab will be constructed with BPQ.020 as the row variable and BPQ.030 and BPQ.050a as the column variables. |
Highlighted items from the proc freq output for skip patterns: