In content validity, you essentially check the operationalization against the relevant content domain for the construct. This approach assumes that you have a good detailed description of the content domain, something that's not always true. For instance, we might lay out all of the criteria that should be met in a program that claims to be a "teenage pregnancy prevention program." We would probably include in this domain specification the definition of the target group, criteria for deciding whether the program is preventive in nature (as opposed to treatment-oriented), and lots of criteria that spell out the content that should be included like basic information on pregnancy, the use of abstinence, birth control methods, and so on. Then, armed with these criteria, we could use them as a type of checklist when examining our program. Only programs that meet the criteria can legitimately be defined as "teenage pregnancy prevention programs." This all sounds fairly straightforward, and for many operationalizations it will be. But for other constructs (e.g., self-esteem, intelligence), it will not be easy to decide on the criteria that constitute the content domain.