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Sometimes a form is nearly identical at every data collection point, but there is a slight difference in the question for some items. For example, at baseline the prompt maybe is "what's your highest pain rating in the last two weeks?", whereas at follow-up, the prompt is "What's your highest pain rating since the last visit?" There are pro's and con's as to how to handle such cases, but the general recommendation is to define as few of variables as possible to that everything possible using different display prompts so that everything lines up in the dataset (see image below).
What to Consider
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