how to determine effects of treatment on multiple subjects how to match a group of subjects for different activity do you use a subject multiple times when you match treated with controls based on age gender activity when comparing subjects and treatments why is an activity biased why do we compare the treatment with control subjects how to evaluate effects of treatment with repeating subjects why do i need to see multiple subjects in a group why use same subject multiple times when a subject is treated and compared to a control how can you compare the treatment and the activity how to match multiple treatments why use the same a subset of activities multiple times can i match treated and control subjects how to analyze the treatment effect of repeating subjects how to determine the effect of treatment when comparing multiple subjects for treatment, which is an example of an appropriate approach to evaluate treatment? how can I test for bias which of the following is the best way to avoid bias caused by looking at the same subject multiple times?