I am looking at allocating hospitals to the following groups, LHA( Low hospital activity) MHA(medium activity HHA(High hospital activity. For which I will then perform analysis on the costs associated with delivering that surgery, as we have costs associated with each hospital and procedure. What I am trying to prove that those hospitals with low activity either have high or low costs.

What I am not sure of is the allocation to groups. Could I use quartile Upper, Middle and Lower or is there a better formula to assign?

I have 137 suppliers of activity with volumes and spend per unit and I wish to review the amount (£) spent by each supplier to demonstrate that low activity increases the unit cost and those with high activity might have low costs per unit. However, I need to agree with what low medium and high is

Thanks for your help in advance