Help with converting percentage decreases into dollars

citizen7 said:

Hello,

I have a question regarding percentage differences. So, I am doing data analysis between an intervention group and a control group. We are looking at hospital days saved (keeping patients out of the hospital), and our intervention group had an 89.82% decrease in days after our interventions (Pre - 3,508; Post - 357. 3,508 - 357 = 3,151/3,508 x100 = 89.82326). The control group had a 79.96% decrease (Pre - 3,857; Post - 773. 3,857 - 773 = 3,084/3,857 x100 = 79.95851). Therefore, that's a difference of 9.86%.

My question is, how can I calculate that 9.86% into a dollar amount? For example, the average cost of a hospital day is $1,500. Therefore, the intervention group saved $4,726,500 (3,151 x $1,500). So, how can I convert that 9.86% into dollars to show the difference in percentage decreases between the two groups? Thank you very much.

Click to expand...

The answer depends on the dollar amount spent. For example, if Hospital C has 1000 hospital days and their costs are (to make thinks easy) $1000/day were to implements the methods of study 1 [the 89.8% savings] they might expect a savings of 99 [actually 98.6 according to your numbers but I assume you would use integers, thus rounding] hospital days and $99,000 over implementing method B [the 80.0% savings].