Maryland’s Department of Legislative Services is pretty good with numbers, but in one particular instance, its numbers don’t add up. That’s the case with its study that assigned Worcester County the third highest crime rate per capita in the state, because it simply isn’t so.

The error of its study’s conclusion is that “per capita” figure, drawn from census data, doesn’t include everyone who spends time — and commits crime — in this county during the course of a year.

This oversight, which is routinely perpetuated in other examinations of Worcester’s economic and social condition, is especially irritating because it ignores the fact that the county is one of Maryland’s most highly populated jurisdictions for about half of the year.

Consider this: Worcester has roughly 52,000 full-time residents, but it also draws close to 9 million visitors and part-time residents annually, giving it a weekly average population more than three times greater than its residential base. Add those visitors and part-timers to the year-rounders, and Worcester is the eighth most populous county in the state.

To look at it another way, if the department’s crime rate numbers were accurate, it would mean that the population equivalent of New York City descended on the county and brought zero crime with it. This is even though if just a 10th of 1 percent of that 9 million people broke the law, that would be 8,000 offenses.

This is no different than concluding that northern Worcester’s section of Route 50 is one of the least traveled highways in the state because that area has a population of just 30,000 or so.

Obviously, that would be incorrect because it excludes the millions of cars that travel that corridor in the spring, summer and fall.

The same rationale applies to the county’s crime rate. Obviously, crime does occur, but taking into account the millions of people who spend time here, Worcester County enjoys one of the lowest rates of crime in Maryland.