This is potentially another time-consuming, difficult task within the capstone experience. Hopefully, you've taken the Tests and Measurement class offered by the department. If so, you know what to look for in a good measurement instrument, and you know how to find one. If you haven't, you need to brush up on some concepts important for evaluating instruments (specifically, their psychometric properties), they are:

• Reliability: basically measures the error in the instrument. It is a percentage that tells us how much of the observed variations are due to variations in true scores. Therefore, you want this percentage to be high. For example, a good reliability in psychological research would be r = .80 or above. That tells us that only 20% of the variability in scores is measurement error, the rest of the variability is a reflection of true variability. You probably don't want to use an instrument that reports reliabilities lower than .80. If you can't find any for your variable, talk to your instructor. There are 2 main types of reliability coefficients you'll read about tests: test-retest reliability, which is a correlation between scores at one time and scores at a second time, and coefficient alpha (sometimes seen as a) is a measure of internal consistency (i.e. how well the various items in the test 'hang together' versus the test-retest that measures temporal stability). Coefficient alpha is probably most commonly found because the researcher only needs to administer the test once to get the reliability coefficient.
• Validity: assesses whether the test measures what it is supposed to measure. Usually you don't get a 'number' for validity, what you get is information from the test manufacturer or the author of the manuscript where the test is introduced telling you something like 'validity was determined to be adequate/good/excellent based on….." (there are a number of ways to test validity). If there is no information on validity, you should be suspicious of the test.
• Norm group: the norm group is the group of individuals that were tested and used as a 'guide' to determine what scores on the test signify. You need to make sure you identify a norm group that is similar to your population. If a test for depression was normed with the elderly, for example, the mean score for the norm group might not be the mean score for your group, or cutoff scores might be different also.

So where do you find the questionnaires you are looking for? First off, determine what your instructor's expectations are. Some instructors will allow you, or even want you, to create your own instrument. Others do not allow you to do this. In both cases, however, you will want to have a few instruments that measure your variable, either to choose from or to use as models to develop your own.

Before we get to 'where to find' the questionnaire and its psychometrics, let's look at some tips about 'what to look for.'

• By now you've become quite an expert in your research area. You've read dozens of articles on the subject and summarized them in an eloquent introduction. Hopefully you've found more than one study similar to what you are planning to do. Use these resources! Go over your literature and write down the name of the instruments used by other, seasoned, published researchers. Make a list and mark on that list each time an instrument has been used more than once. You may end up with a list, for example, of 5 depression questionnaires, one of which has been used by 70% of the researchers. That probably gives you a clue as to which to consider most strongly.
• Other factors come into play also. If the questionnaire that is used the most is an 'interview format' questionnaire, that will probably be out of the question for you, since it will take hours and previous training to administer it. Go for the next most used that is also shorter, self-report, and still has good 'psychometric qualities' (reliability, validity, etc.)
• You may find that an instrument you are considering is not appropriate based on language use, questions used, etc. Remember you may have a population to work with that may be different from what others use (college age versus elderly, for example).
• We are supposing that questionnaires used by published authors have excellent reliability and validity, and that they are probably among the best available. That is more than likely an appropriate supposition since these researchers have been evaluated a number of times by their peers (grant funding, publishing). However, you still need to check to make sure the instrument is psychometrically valid and appropriate for use by you for your study, so ultimately, the decision is yours as to what instrument to choose.
• And be aware that this is one of the most important decisions you will make in designing your study. A poorly selected instrument may result, at the end of the semester, in findings that don't make sense and don't match the existing literature, leaving you at a loss as to how to make heads or tails of your study. Researchers spend a great deal of time selecting the appropriate instrument for their studies, you do the same!

Useful links to find measures online:

Carver University of Miami

IUPUI Library Sources for Psychological Tests