A multiple choice test with nine statistical questions was sent to a random sample of Danish doctors to assess their knowledge of elementary statistical expressions (SD, SE, p less than 0.05, p greater than 0.05 and r). One hundred and forty eight (59 per cent) of 250 doctors answered the questions. The test was also completed by 97 participants in postgraduate courses in research methods, mainly junior hospital doctors. The median number of correct answers was 2.4 in the random sample and 4.0 in the other sample of doctors. It is concluded that the statistical knowledge of most doctors is so limited that they cannot be expected to draw the right conclusions from those statistical analyses which are found in papers in medical journals. Sixty-five per cent of the doctors in the random sample stated that it is very important that this problem is raised.

Biometry↗

PubMedDate not supplied

Regression toward the mean in fertility research--an empirical study of semen quality.

Regression toward the mean denotes circumstances, where extreme observations tend to normalize at repetition. The phenomenon is caused by random variation and may occur whenever mainly persons with extreme values are subject to repeated examinations. We furnish empirical evidence that the phenomenon may be quantitatively important in fertility research with regard to some, but probably not all indicators of semen quality.

Fertility↗

PubMedDate not supplied

Radiologic findings and weight loss following gastroplasty for morbid obesity.

Gastroplasty aimed at treatment of morbid obesity creates a small proximal pouch and a narrow stoma to the remainder of the stomach. In 11 consecutive obese patients subjected to gastroplasty radiologic examinations of the stomach were performed before operation and one week, 3 and 12 months postoperatively. All stomachs were normal before operation. A significant decrease in pouch area and increase in stoma diameter were registered over the observation period. There were no statistically significant correlations between postoperative weight loss and stoma diameter or pouch area. Nor was retention in the pouch one week after gastroplasty related to weight loss. Radiographic evidence of gastroesophageal reflux was present in only one patient. The described method of follow-up is evidently not suited to predict the outcome of gastroplasty.

Adult↗