Please find the most recent iteration of my protocol attached. Thanks!
Hi Joe,
The interrupted time series works best for interventions that will occur in that particular institute in which it will be its own control. Usually the control data is collected prior to the intervention's implementation. Then, the intervention data is collected. What is great about this is that the before and after measurements will allow for the assessment of a trend and auto-correlation. As discussed in class, since there is often no randomization in the interrupted time series, inference of causation is weaker. Re: the unit of analysis, I think what you mean is that the patient is the unit of analysis and the number of mental health visits before and after the intervention will be your data points to compare. It has been great seeing your protocol evolve throughout the course.
Vicky
Hi Joe,
I agree with Vicky that an interrupted time series sounds like the best type of study and that the unit of analysis will be the patients.
An alternate assessment you could consider would be to measure proportions of patients with a dichotomous outcome, such as
1) proportion of patients who had a mental health visit completed in the past three months
2) proportion of patients who had a primary care visit completed in the past three months
and measure these proportions at several different times points before and after the study.
Maria
Hi Joe,
I agree with Maria and Vicky that interrupted time series using the patient as the unit of analysis would be a good analytic strategy. Maria's point of trying to come up with alternate outcomes is also interesting. However, it might be difficult to figure out an adequate control for the dichotomous outcomes she mentioned. Should the patient be their own control? And is there a target for the proportion of patients who have mental health visits and primary care visits? You would also have to think very carefully about your time period. Is three months an adequate amount of time ot observe a difference?
The good thing about a study at the VA though is that your sample size always has the potential to be big!
Good work on your protocol so far, as others have said, it's been nice to see it progress over time!
Maria