Press Ganey is already moving the business of surveying doctors well past emergency rooms and hospital visits.

FORBES: Why Rating Your Doctor Is Bad For Your Health

But what exactly are Press Ganey and its two main rivals, the Gallup polling company and the publicly traded National Research Corp.

FORBES: Why Rating Your Doctor Is Bad For Your Health

And it means ever more clout for operations like Press Ganey.

FORBES: Why Rating Your Doctor Is Bad For Your Health

Hospitals had to turn to companies like Press Ganey, which administers the federal survey for them and rates other units not covered by the mandate, like the ER.

FORBES: Why Rating Your Doctor Is Bad For Your Health

But William Sullivan, the Illinois ER doctor, says that Press Ganey reports monthly results to his hospital even when there are as few as eight to ten surveys.

FORBES: Why Rating Your Doctor Is Bad For Your Health

Press Ganey admits that survey sample sizes sometimes are too small and says a minimum of 30 responses for an ER is necessary to draw meaningful conclusions from its data.

FORBES: Why Rating Your Doctor Is Bad For Your Health

Earlier this year, Citrus Valley was named one of the most improved hospital systems in the country in terms of inpatient satisfaction by Press Ganey Associates, a provider of healthcare analytics.

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Press Ganey is helping hospitals fulfill their mandated obligation.

FORBES: Why Rating Your Doctor Is Bad For Your Health

Accordingly, hospitals kowtow to Press Ganey.

FORBES: Why Rating Your Doctor Is Bad For Your Health

Instead, that move empowered Press Ganey.

FORBES: Why Rating Your Doctor Is Bad For Your Health