P.Mean: Reading abstracts instead of the full article (created 2008-11-05).

An interesting inquiry on the Evidence-Based Health email discussion group generated a lot of responses. A busy clinician has a limited amount of time to answer a clinical question. They carry out a quick search and find 5 decent abstracts. They have two options: 1) Look at one full-text article. 2) Look at 5 abstracts. Which do people think is preferable? It's a tricky question because both approaches have problems. Here are my thoughts on this issue.

What are the limitations of reading just the abstracts?

  1. The abstract may not clearly state information about how the data was collected (e.g., blinding) or how the data was analyzed (e.g., intention to treat analysis) that you would need in order to properly evaluate the strength of evidence.
  2. The abstract may focus on the wrong outcome measure. The abstract may, for example, only include details about the outcome measure with the small p-value rather than the outcome measure that is important from the patient's perspective.
  3. The abstract may not clearly state the risks of the treatment preventing you from assessing the cost-benefit ratio.

In a perfect world, abstracts would provide all the details that you would need in order evaluate the article appropriately. There is, however, a fair amount of empirical evidence that abstracts leave out important details. In some cases, it is even worse, because the abstract contradicts important details in the paper itself.

A busy clinician has to trust the system. Some abstracts are misleading, but the time lost verifying whether the contents of the abstract are a fair representation of what appears in the article itself is too big a price to pay, if the clinician is truly as busy as you say.

Reviewing the abstracts has the extra benefit of assessing the robustness of a finding across different patient populations and different research designs.

Besides, if you wanted to choose intelligently which among the five articles you had to read the full text of, you'd have to read the abstracts anyway.

What are the limitations of reading just the abstracts?

  1. The abstract may not clearly state information about how the data was collected (e.g., blinding) or how the data was analyzed (e.g., intention to treat analysis) that you would need in order to properly evaluate the strength of evidence.
  2. The abstract may focus on the wrong outcome measure. The abstract may, for example, only include details about the outcome measure with the small p-value rather than the outcome measure that is important from the patient's perspective.
  3. The abstract may not clearly state the risks of the treatment preventing you from assessing the cost-benefit ratio.

In a perfect world, abstracts would provide all the details that you would need in order evaluate the article appropriately. There is, however, a fair amount of empirical evidence that abstracts leave out important details. In some cases, it is even worse, because the abstract contradicts important details in the paper itself.

Of course, we need to train clinicians in rapid critical appraisal and speed reading so that they can learn to read the full text of five articles in the time it used to take to read five abstracts. Some teachers of EBM advocate not handing out papers in advance, but making students read the papers in class so that they are forced to read quickly and hone in on the important details. Alternately, the health care organization that employs the clinician should supply the appropriate resources to allow someone in the medical library to offer a critical appraisal of these five articles to a busy clinician on short notice.

Creative Commons License This work is licensed under a Creative Commons Attribution 3.0 United States License. This page was written by Steve Simon and was last modified on 2010-04-01. Need more information? I have a page with general help resources. You can also browse for pages similar to this one at Category: Critical appraisal.