Source filters: choose the evidence behind an answer

What the source filters do

AskMed's source filters control which medical sites are searched and how many sources an answer cites. Tap Filters next to the question box to open the Filter sources sheet. At the top, the Number of sources slider sets any count from 3 to 12, with 8 as the default. Under Sources, four switches turn whole groups on or off: Scientific articles, Clinical guidelines, Drug labels and Books / references. Under Study types, four more switches choose which research to cite: Meta-analysis, Review articles, Clinical trials and Other, which covers observational studies and case reports. A toggle called Remember filters for this session keeps your choices for the next questions, and Reset Filters puts everything back to the defaults. Under the question box, a short line such as "8 sources · guidelines, labels" shows what is set, so you can see the filters before you send. Retrying a question uses the same filters it was asked with.

How the filters work

The filters work by changing the search AskMed runs before it writes anything. Each Sources switch stands for a fixed group of medical sites. Scientific articles covers PubMed, PubMed Central, the Cochrane Library, NEJM, The Lancet, JAMA, The BMJ and specialty journals. Clinical guidelines covers NICE, the US Preventive Services Task Force, IDSA, ESC, KDIGO, GINA, GOLD, ACOG, CDC, WHO, ECDC and the National Cancer Institute. Drug labels covers the FDA and DailyMed, plus national drug registries when a question names a product. Books / references covers the NCBI Bookshelf with StatPearls, the MSD and Merck Manuals for professionals, BMJ Best Practice and NIH. When a group is off, its sites are left out of the search, even when one sits inside an allowed site, such as PubMed inside nih.gov. Study type switches apply only to research articles: AskMed judges each article's type from its title and excerpt and cites only the types you kept.

The number of sources is a target, not a quota. If the search finds fewer relevant sources than you asked for, AskMed cites fewer rather than padding the answer with weak or off-topic ones.

When source filters help

Source filters help when the kind of evidence matters as much as the answer. A family doctor checking current management can turn on Clinical guidelines only and get an answer built from guideline bodies such as NICE or ESC. A pharmacist can keep Drug labels on to see label language on interactions, warnings and contraindications, without doses. A researcher can keep only Meta-analysis and Review articles to see what systematic reviews concluded before reading single trials. A medical student revising a topic can choose Books / references for StatPearls and MSD Manual explanations that read like a textbook. A nurse who wants a quick, focused answer can lower the slider to 3 or 4 sources, while anyone preparing a talk can raise it to 12 for a wider spread of citations. Filters also help when an answer leans on a source type you don't trust for that question: turn that group off and ask again.

Other AI tools rarely let you choose the sources at all; see AskMed vs Perplexity for one comparison. Get AskMed on the App Store for iPhone and iPad, on Google Play for Android, or use it on the web.

Limits of source filters

Source filters narrow where AskMed looks, so they can also narrow what it finds. With only one group switched on, or only one study type, the search may return too little to answer, and you will see AskMed's fixed no-source reply instead of an answer; widen the filters and ask again. Each group is a fixed list of sites, so a journal or guideline body that is not on the list can't be added through the filters. Study types are judged by the AI from each article's title and excerpt, not from a database label, so an occasional article can be placed in the wrong type. The filters choose the kind of source, not its quality or its date: a guideline can still be older than a recent review, and AskMed's answer is told to say when guidance has changed. Filters never change AskMed's rules, so no setting brings back drug doses.