Guilt By Statistical Sampling

From the Des Moines Register: 'Arrest near' in case of missing Crawford County park fees

Crawford County officials say they’re close to making an arrest in the suspected theft of at least $32,598 in camping fees.

County officials called in state auditors last year after raising concerns about the camping fees that had been collected at Yellow Smoke Park. Those concerns surfaced after the retirement of Alan Disburg, the park ranger at Yellow Smoke for the previous 16 years.

Auditor of State David Vaudt issued a written report on his office’s findings today. The report notes that Disburg’s duties included collection of the camping fees, oversight of the camping-registration ledger and preparation of the bank deposits.

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Using checks or cash, campers at the park pay fees of roughly $15 per night. The campers place their payments in envelopes that are deposited in locked boxes on the campgrounds. Those payments are then collected by park employees, recorded in a camping-registration ledger, and eventually deposited in the bank.

In 2006, during the first full season of camping after Disburg’s retirement, the park collected and deposited $78,758 in camping fees – a 14 percent increase from 2005. At the same time, the percentage of all recorded fees that campers paid in cash, rather than checks, increased from 10 percent to 22 percent.

As a result, the amount of fees paid in cash that were deposited in the bank during 2006 was two and a half times greater than the amount deposited in 2005.

Using the 2006 data as a benchmark, state auditors calculated the expected amount of cash the park would have collected in camping fees between 2002 and 2005. They determined that at least $32,598 was collected during those three years but never deposited in the bank.

Now, barring a complete confession from the retired park ranger, I would have some trouble with the prosecutions case were I a juror. For starters, I would consider using a single year's worth of data woefully insufficient to establish guilt, let alone the severity of the rangers crime. There would be just too many unanswered or unanswerable questions. How much does attendance in the park vary over the years? How much does the ratio of checks-to-cash vary in customer payments? Did the relatively high price of gas cause more people to vacation closer to home and lead 2006 to be an unusually busy year? Even if it can be shown that the park ranger was indeed stealing, is it safe to assume that he stole at an even rate over several years worth of employment?

Basically, the county is claiming that the ranger stole an amount of money that may, or may not, have actually existed. I know that is the nature of "cash" businesses and they should have some way of dealing with the thieves in their midst. But it seems to me they should need to work harder to make this kind of case. Otherwise we will all be at risk of being incarcerated because of a statistical outlier.