We have over 10 years of data on a number of hospitals that we regularly transport patients to. This past February, a new hospital (1830) opened that has substantially altered our transport patterns, especially taking away from the previous primary destination (1247).
Destination Dec Jan Feb Mar Apr 1247 117 140 131 65 77 1017 75 69 54 45 31 1818 56 58 43 46 39 1830 - - 30 125 86
I want to evaluate the overall impact (improved in-service times, reduced mileage/vehicle costs, etc...) of the new facility. What is the appropriate manner to evaluate the new facility? Should I compare equal periods prior to and after it opened? Or, can I evaluate the prior year and the period since it opened? Any help is appreciated.
EDIT: I'm not sure that I have too much seasonal/cyclical variance in my long-term data. Here's a chart that has the previous 5 year history (each point is a 2-week period). I've highlighted total patients transported (with 26 period moving average), and the destination hospital in question.