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Self Experiments. Analysis of Patients’ Causal Diaries. System Change for Exercise Maintenance in Older Cardiac Patients. National Heart and Blood Institute 09/1/2006- 09/1/2009 PI: Shirley Moore RN, PhD Co-PI: Farrokh Alemi, PhD. Exercise Causes & Constraints.
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Self Experiments Analysis of Patients’ Causal Diaries
System Change for Exercise Maintenance in Older Cardiac Patients National Heart and Blood Institute 09/1/2006- 09/1/2009 PI: Shirley Moore RN, PhDCo-PI: Farrokh Alemi, PhD
Exercise Causes & Constraints “… I realized how many great reasons I had to skip my workout today. First: rain… Second: low quality sleep after a night spent with my 17-pound cat getting tangled in the blinds. How could anyone exercise after a night like that?” Paige Waehner
Exercise Causes & Constraints “What makes me exercise is that I have to take a shower and the only place I can take a fun shower, with lost of water, is at the gym. My shower at home does not have much water pressure. I have no choice but to go to the gym.” 68 years old woman
Exercise Causes & Constraints “When I bike, I do not exercise. I commute to work. ” 42 year old man
Exercise Causes & Constraints • People have different reasons • One solution does not fit all • People have wrong perceptions • I fail because of my environment • I succeed because of myself
Exercise Causes & Constraints • People have different reasons • One solution does not fit all • People have wrong perceptions • I fail because of my environment • I succeed because of myself We cannot succeed, if we do not know why we have failed
Health Sustain exercise post rehab Objectives
Health Sustain exercise post rehab Understand causes of & constraints for exercise Objectives
Health Sustain exercise post rehab Understand causes of & constraints for exercise Conduct self experiments: Maintain diary, analyze data, repeat the process. Gain insight. Objectives
Self Experiments • List possible causes/constraints • Trace occurrences • Analyze data • Small data sets of 10-14 data points
Bike to work Shower at gym Sleep early Rain Diary
14-day Diary Too little data for most statistical methods of analysis
Obvious Lessons • No variation in outcomes: • No exercise in the entire 2 weeks • Exercise every day • No variation in causes: • Always present cause • Always absent cause
Causal Analysis • Sequence • Cause precedes exercise • Association • When the cause is present, exercise should be likely • Counter-factual • If the cause is absent, and no other causes are present, exercise should be unlikely
Methods of Analysis • Logistic regression • Bayesian networks • Causal analysis
Method 2: Bayesian Network • Markov blanket • Use of conditional probabilities • Serial conditional independence • Common cause • Common effect
Method 3: Causal Analysis Conditional 1-Counterfactual
Study Phase I • Which of the methods is most accurate? • Which method is easier to understand? • Which method is easier to use?