Research: What can you believe about what you read?

Here's a sobering look at why we need to be a bit cautious when we are informed that such-and-so is the assured results of modern science. Take "epidemiology", for instance:

Even the way epidemiologists frame the questions they ask can bias a measurement and produce an association that may be particularly misleading. If researchers believe that physical activity protects against chronic disease and they ask their subjects how much leisure-time physical activity they do each week, those who do more will tend to be wealthier and healthier, and so the result the researchers get will support their preconceptions. If the questionnaire asks how much physical activity a subject’s job entails, the researchers might discover that the poor tend to be more physically active, because their jobs entail more manual labor, and they tend to have more chronic diseases. That would appear to refute the hypothesis.

Must reading if you are interested n health science issues.