I think "representation" is the best translation for the term "Abbildung" in this particular context. The term "indication" could also be used but my first choice would be "representation".

so they know eg where to invest / how they do in comparison with other hospitals (?)

I think they are writing about how cost-efficient the medical work is, since it is about "Abrechnung". Then productive efficiency seems to be the phrase. Leistungsfähigkeit can mean productive efficiency according to leo.org.

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Note added at 52 mins (2010-09-27 15:13:11 GMT)
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If you do not like the word overview, "mapping" is another option.

One more option

German term (edited): für die Abbildung der medizinischen Leistungsfähigkeit

Leading hospitals are learning that there are relatively painless alternatives to the ongoing struggle with performance inefficiency, low revenue, and inadequate reimbursement rates. Physician Advisors, when leveraged appropriately, improve overall hospital performance and minimize medical and financial risks. They can improve medical management by evaluating the efficiency of medical services rendered with respect to the revenue-cycle continuum.
http://www.allconferences.com/conferences/2006/2006113014065...

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Note added at 21 hrs (2010-09-28 12:14:28 GMT)
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"efficiency of medical services"
http://shortify.com/11140