Positive-findings bias (or positive-publication bias) occurs because lot courted. studies with some positive findings, such as the effectiveness of a certain med- ical treatment, are more likely to be published than studies with no significant findings. After all, who wants to read that something doesn't shrink a tumor? But the basic laws of probability suggest that if studies with no significant findings are less likely to be published, the result may be misleading to experts rt in the field. Consider a simple numerical example. Suppose that ten teams of researchers are independently examining whether or not a new drug is effect tive in shrinking a certain kind of tumor. Further assume that nine research a teams find that it is not effective while one team finds positive results. This positive finding could easily be the result of chance; a reading of all ten stud- na ies would cast serious doubt on the effectiveness of the treatment. led But medical experts may not get to see all ten studies. The researchers Ic1- with negative findings may not submit their research for publication; and, if ose submitted, medical journals may not be inclined to publish it. On the other t in hand, the positive findings are more likely to be published or receive other set Public attention. The overall result is misleading because medical experts are exposed to the positive findings of one study but not to the far larger num- the ber of other studies with more discouraging results. Medical journals are e the How attempting to remedy this problem by requiring that all studies to beconsidered for publication be registered before they begin, so that the journal will have a greater awareness of all the research being done on a topic and the proportion of positive findings. Good data are essential to good policy. Gathering such data requires both expertise and extraordinary resources. One important role of government and the nonprofit sector is gathering information that is essential for the public policy research that helps to improve our lives