[EpiData-list] problems with calculations during double entry

Hi,

I have a problem with results of calculation during double entry. During double entry, all calculations give same results as first entry except only for few subjects. I checked my formulae with other software and they look OK. This bug is not systematic that’s why I have difficulties finding errors. I don’t understand why this bug appears only for few subjects. They have not the same characteristics.

Who can tell me what king of error it could be, because I don’t know anymore what to looking for?

Below, calculations :

pspef AFTER ENTRY IF (sex = 1) and (height < 162.6) THEN pspdpef=(height * 0.073) - 5.98 ENDIF IF (sex = 1) and (height > 162.5) THEN pspdpef=(height * 0.125) - 13.14 ENDIF IF (sex = 0) and (height < 152.6) THEN pspdpef=(height * 0.079) - 6.79 ENDIF IF (sex = 0) and (height > 152.5) THEN pspdpef=(height * 0.064) - 3.94 ENDIF IF (sex = 1) THEN pssdcpef=(pspef - pspdpef) / (pspdpef * 0.18) ENDIF IF (sex = 0) THEN pssdcpef=(pspef - pspdpef) / (pspdpef * 0.2) ENDIF psppef=(pspef/pspdpef)*100 END END

pspdpef NOENTER END

pssdcpef NOENTER END

psppef NOENTER END

Example : sex = 1 , height = 132.8, pspef = 4.90

First entry (good results) pspdpef = 3.71 pssdcpef = 1.78 psppef = 132.1

Double entry pspdpef = 3.71 pssdcpef = -1.15 psppef = 79.2

Thank you in advance for your help.

Marie-Pierre

Strippoli Marie-Pierre Institut of social and preventive medicine Department of Epidemiology and Biostatistic Paediatric Epidemiology Finkenhubelweg 11 3012 Bern Tel: +41 (0)31 631 35 07 Fax: +41 (0)31 631 35 20 http://www.ispm.unibe.ch