GIGO "garbage in, garbage out" applies to many aspects of our lives, searching for and finding information included. A few rules of thumb apply. I have always wanted to use the word "heuristic" in a sentence and have the opportunity here but will stay my hand.
The smaller and simpler the system the easier it is to find what you want. It is pretty easy to find pertinent Cochrane systematic reviews from the the 8,000 in the Cochrane database. It is quite a bit harder to find what you want in PubMed with its 26,000,000 articles.
The larger and more complex the system the more time it will take to create an effective search.
What percentage of all the relevant articles about a topic a search finds directly correlates with the time it takes to create the search.
Precision and recall are often used in information science to describe how well a search functions. You can compare them to sensitivity and specificity. A very precise search returns a small number of results and is likely to miss useful articles. A search that has high recall finds nearly everything about a topic; however much of what is found is irrelevant. A high recall search requires much more time and effort to evaluate the results. The take aways? There is a tradeoff between precision and recall in searches. There is no such thing as a perfect. It is necessary to consult multiple sources to lower the chances of missing important papers.
One of the cornerstones of Evidence-Based Practice (EBP also called Evidence-Based Medicine or EBM) is the PICO model. PICO is a framework which helps questioners frame a clinical question.
Wearing my library hat, what follows are methods to create phrasing for use in databases or search engines.
Searching is a task that is only judged by how well it does the job of finding the pertinent information you need for work and school.
The search process is iterative. It is rare to create a good search on a new topic in your first attempt. There is usually some trial and error, with gradual improvement
Formulate the Search: To use a database effectively, think before you type!
1. After some background reading your original question may need to be reformulated; it may begin to look like several questions or you may answer it with background information. What might be a problem with not looking at foreground sources?
2. Create a simple, searchable question. This is the single most important (and difficult) step!
What does “simple searchable” mean? Avoid unnecessary detail. Carefully choose your words. Be willing to change words if they do not seem to work when you do your search. 4 construction methods to try out follow:
a. Make a simple sentence of your question. Use the subject and object as search terms, avoid the verb as search engines are usually no good with those.
b. Write down a list of all the concepts within your topic. Select the most important two or three as your search terms.
c. Most time consuming, organized and effective method: Create a table of concepts. Select two or three. Think of synonyms for each. String all that together and use that as your search.
d. Use the PICO model. This approach is derived from Evidence-Based Medicine (EBM), or more properly EBP (EB Practice). It is probably most useful for treatment questions.
What these various methods look like follow below. At the bottom of the box is an example of each method in action.
a. One searchable sentence:
b. Concept List: Examine your question, choose the most important 3-4 concepts:
c. Concept/synonym table: