How can you say that it is valid to use questionnaires to measure abstract ideas?

How could you actually consider questionnaires as a valid way to measure abstract ideas such as personality, values and attitudes?

How can you say that it is valid to use questionnaires to measure abstract ideas?
Actually, it is not so easy to measure ones personality,values and attitudes, but, some idea about such qualities can definitely be have by certain tools. Questionnaires are one such tool being adopted by many organizations. Validity or otherwise character of the questionnaire depends on the type/ nature/ length %26amp; width, and relevance of the questions being asked. In case the questions have been framed properly keeping the target public in site, then definetly there is possibility of getting reliable results, and reverse case is also true. One can not be able to hide qualities such as his personality, values and attitudes in case of properly designed questionnaires.
Reply:no. but in order to actually get any type of empirical evidence you can gather answers in an open format, but then record the number of times certain words or phrases appear in those answers. otherwise i feel like giving them multiple guess is like giving them only a set of proper answers. they are forced to make a choice between answers- not tell how they feel. and words int eh possible answers that are given can trigger a person to answer one way or another depending on whether there is a positive or negative connotation, or a certain order to the answers, etc.
Reply:The only it way it could even be remotely valid, is that it is possible that it could be reflection of how the person is at that moment in time during the test taking in regards to that particular question. Personality changes, but it doesn't change at a high velocity. There are general ideas of how a person is "typically" in most circumstances in his or her life, until the person makes a radical shift in perspective. In other words if I asked you "On a normal day, if you had $5 in your pocket, and your friend asked you for $2, would you A. Give the money and request it be returned. B. Give the money and say nothing else. or C. Refuse to give the money because your friend is a lowlife. IF you answere A. I could tell that most generally you are typically frugal and like to give and recieve equally in most things. If you answered B. I could tell that you were more carefree and laid back in most things. If you answered C. I could tell that you were more conceited and self-cenetered in most things. These questions may seem specific on the surface, but actually they are looking for the abstract response in regards to the question.