The discovery by K.S. Joseph and Michael Kramer of the misreporting of gestational age for Canadian preterm births in 19721 may indicate not only rounding to the nearest lunar month or half month, but also the recognized bias for even versus odd numbers. This bias is a form of digit preference, which has been defined as "a preference for certain numbers that leads to rounding off measurements. Rounding off may be to the nearest whole number, even number, multiple of 5 or 10 ...."2 Interested readers will find a catalogue of biases in an article by David Sackett.3