Evaluating studies: First weigh all the evidence - DVM
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Evaluating studies: First weigh all the evidence


The terms "the results are approaching significance" and "there is a trend toward significance" are misleading. Results should be considered to be either significant or not significant.

The power of the study is its ability to demonstrate an effect if one really exists and is determined by the sample size, variability and magnitude of the effect.

Studies that have small numbers of subjects are less likely to detect a significant difference unless the magnitude of the effect is large. Studies that have large numbers of subjects may detect a difference that is not clinically relevant.

One of the biggest issues with veterinary studies is small sample size. The majority of studies have small numbers of subjects, limiting the accuracy of findings.

Confounding and correlation

Confounding is the distortion of the effect of one factor due to the presence of another.

It often is possible to identify and correct for confounding factors with the appropriate statistical analysis.

Correlation of two variables is a measurement of how likely these variables are related. Keep in mind that correlation should not be taken to be cause and effect. It is entirely possible for two variables to be related by coincidence.

Suggested Reading
Although it is more time-consuming, it is important to read through the entire article so that we can judge the validity of the results for ourselves.

Only by doing this can we decide if the findings in a study warrant a change in the way we practice veterinary medicine.

Dr. Cronin earned her DVM degree from Cornell University in 1990. She completed an internship at the Animal Medical Center in New York and a medical oncology residency at North Carolina State University. She is a diplomate of the American College of Veterinary Internal Medicine in the specialty of oncology. After completing her residency, she was lecturer at the University of Pennsylvania Veterinary Teaching Hospital and a medical oncologist at Angell Memorial Animal Hospital in Boston. In 2001, she co-founded the New England Veterinary Oncology Group in Waltham, Mass.


Source: DVM360 MAGAZINE,
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