 Sometimes, the variables studied in psychological research are difficult to measure. When designing a research project about a variable, like happiness, relationship quality, or extraversion, where do you start? Variables like personality traits, emotional states, attitudes, and abilities are called constructs. There are three library tools that can help you find tests scientists have developed to measure constructs. For example, let's say we're interested in knowing more about empathy in sibling relationships. First, we need to find other studies that have examined this topic to see how they measured empathy. Psychinfo is a great tool for this if you do a search for your terms. Most articles in Psychinfo will list the tests and measures the researchers used. For example, this study used the index of empathy for children and adolescents to measure empathy, as well as some other tests related to family relationships and teen development. We could find out more about this measure by reading the methods section of the article. A second place we can look for measures for empathy is mental measurements yearbook with tests in print. Here we can find commercially available tests and measures and detailed reviews of many of them. Let's try a search. We could try browsing by test category, like personality, or we could try a keyword search. It looks like this test measures empathy as an overall assessment of emotional intelligence. The last place to look for tests and measures is psych tests. This database is a collection of tests from the American Psychological Association. Sometimes you'll get a description of the test, but sometimes you can see the full text of the instrument. Before searching, choose select databases and limit your search to just psych tests, then try a keyword search. You might find it helpful to narrow your results using the filters on the left. A very important filter is the construct filter, which lets you limit to tests that focus on a particular construct. In this case, empathy in general, broader concepts like emotional intelligence, or narrower concepts like effective or cognitive empathy. You might also find the age group and instrument type filters helpful to find a test appropriate for your population and a desired methodology. Another way to explore psych tests is through the browse feature. If you need help with tests and measures, you can always ask a librarian, or check out this video on evaluating tests and measures.