## 3.1.3 Building blocks method

When you start searching you might type in some search terms to see what information you can find. If you use suitable search terms, this will often yield pretty good results. You can find even more useful sources by searching systematically. One way of searching systematically is the building blocks method. The building blocks method is a way to combine multiple search terms in one search.

With the building blocks method, you divide your search into different aspects. For each aspect of your question you collect search terms. Combine search terms from all aspects into one search string.

How you can best combine the search terms into one search string can differ per search system. The help-function of a search system often explains how you can best search in it. There are search systems that automatically combine your search terms. Sometimes you have multiple search bars to fill in search terms and sometimes you must put all keywords in one search bar. In the latter case, it is wise to use Boolean operators (see 3.2.1 Search technique for more information).

- AND is used to combine different subjects
- OR is used to combine all synonyms, translations, or abbreviations of one subject. When you use OR between the synonyms, then the search includes them all. At least one of these words must be included in the search result.

Example

Aspect | Search terms
--- | ---
Overweight | overweight, obesity, healthy weight
Canteen (HBO) | school cafeteria, canteen, schools, higher education schools, caterer, students
Measures | measures, prevention, policy, guidelines, choice of foods, selection of foods

You have collected the above search terms because you are looking for literature on 'measures that school canteens take against obesity'. If you only search for obesity, there is a good chance that you will get a lot of search results, most of which are irrelevant. If you add search terms for the other aspects, you are already looking more specifically. For example; obesity, policy, school canteens. You will have fewer results but what you find is more relevant. This can be done even better by combining more of your search terms with Boolean operators. Use OR to combine search terms within one aspect and put AND between different aspects.

(overweight OR obesity) AND (school cafetaria OR canteens OR schools) AND (measures OR prevention OR policy OR guidelines)
With the above search string, one of the words from every aspect must be included in the search result. So, you could find an article that contains these: obesity + canteens + prevention. Build up such an extensive search string by testing which search terms work well. You can do that by always adding or omitting words. Continue until you have the right search results.

In the next section you can read more about how search techniques, such as Boolean operators, work and which tips and tricks you can apply.