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EVERY 10 YEARS WHEN THE census is made, many people complain that they undercount people in cities like Washington, D.C. Now a study using census data says that D.C. Public Schools (DCPS) may have 13,000 students fewer than reported (“City Desk,” 5/12). Why does this show that DCPS can’t count? It is just as reasonable to believe that the census really does undercount D.C. residents.

As a DCPS employee with some knowledge of student records, I am sure that some students are counted twice. When you have many students that move several times a year without bothering to inform anyone, this is inevitable. But there are nowhere near 13,000 duplicate or phantom students. Spread over the entire city, this would be about 75 extra students at each school. In a school with only 200-300 students, 75 phony students would be quite obvious. It is just an unlikely thing.

I do not understand why people are so eager to believe data that is based on possibly flawed census data looked at in the abstract and find DCPS data based on real people unbelievable.

Dupont Circle, via the Internet