Wikipedia:Wikipedia Signpost/2008-06-30/Dispatches

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Dispatches: ADD TITLE HERE

By Laser brain, Tim Vickers and ??? Eubulides, June 30, 2008

Sources in biology and medicine

Types of sources

In general, the most reliable sources in biology and medicine are peer-reviewed publications in scientific journals. An excellent starting point is PubMed, which is a database of publications in biology and medicine. Although this is the most comprehensive database, many of the journals it lists restrict on-line access, so there is the alternative of PubMed Central, where all the articles are free.

There are two main types of sources in the scientific literature. Primary publications, which are papers describing novel research for the first time, and review articles, which try to summarize and integrate other people's work into an overall view of a topic. In medicine there are also clinical trials, which test new treatments, and meta-analyses that bring together the results from many clinical trials and try to get an overall view of how well a treatment works. It is usually best to use reviews and meta-analyses if you can, since these give a balanced and general view of a topic, and are usually a bit easier to understand!

Assessing the "quality" of a source is difficult. To know how much weight to give a particular publication you usually need to have a good grasp of what has been published before, and how this fits into other people's results - this is why reviews are so useful, since they do this for you. Two general rules of thumb can be useful though. First, if a biology/medicine journal is not listed in PubMed, it is of doubtful quality - the journal published by the Creation Research Society would be one example. Second, the impact factor of the journal can tell you how influential it is. This number measures how often a paper in this journal is usually cited by other papers - good journals publish papers that other people find useful, while bad work is usually ignored.

Searching PubMed

There are basic and advanced options for searching PubMed. In the basic option you enter some keywords, such as "breast cancer" - and will get over 180,000 results that include this specific phrase. Just above the list of hits there are two tabs, one labeled "All" and the other "Review". If you click on the "review" tab it will take you to a list of about 14,000 academic reviews.

To look at one of these in more detail, just click on the title - such as RE Coleman's review on Risks and benefits of bisphosphonates.. This takes you to a summary (the abstract) of the review and gives you a list of authors and, on the right, a list of related articles. In the top right there can be a link to the journal website (here it is the British Journal of Cancer). At the bottom of the abstract is a number called the PubMed ID number, which is PMID: 18506174 in this instance. To cite RE Coleman's review in your article, just copy the PMID number into this tool.

To do an advanced search with the same keywords, go back to the search screen, enter "breast cancer", as before, and then click on the "Limits" tab just below the search box. This takes you to a set of options that allow you to limit your search to particular dates, types of articles or topic areas. To search for meta-analyses, for example, tick that box in the section on Type of Article and hit "search". You will now get a list of about 460 meta-analyses that deal with breast cancer.

Free versus non-free sources

Other things being equal, it is better to cite a source whose full text is freely readable so that the general public can follow the link to the source. If your Pubmed search finds a lot of sources, you can restrict yourself to the freely readable ones by clicking on the "Limits" tab and checking the box labeled "Links to free full text". However, the best and most-reliable sources often require a fee or a subscription, and non-free sources should be preferred if they are significantly better than free sources and if you or some other Wikipedia editor can read them.

Abstracts versus full text

Often an article's abstract is freely available to all even when its full text is not. When searching for sources, it typically better to find everything you can, including abstracts of papers you can't read, and use that to get a feel for what reliable sources are saying.

When it comes to actually writing a Wikipedia article, it is generally not a good idea to cite a source after reading only its abstract, as the abstract necessarily presents a stripped-down version of the conclusions and often omits motivation and background that is crucial for understanding what the abstract says. You may need to visit a library in order to get the source, or ask another Wikipedia editor to read the source for you and summarize what it says; if neither is possible you may need to regretfully cite some other, lower-quality source.

Public domain sources

Some source are in the public domain. These include many U.S. government publications, such as the Morbidity and Mortality Weekly Report of the U.S. Centers for Disease Control and Prevention. You can incorporate public-domain text bodily into a Wikipedia article without infringing copyright, which can help you write an article on a new topic quickly. However, in such cases you should follow scholarly practice and cite the source, putting quote marks around direct quotations. Generally speaking it is better to summarize sources even when they are public domain, as they typically are not encyclopedias and are not written in an encyclopedic style.