How do you critique reliability & validity of studies?

A new family planning consultation is implemented at a local community health clinic, which experiences a high percentage of women reporting unwanted pregnancies. Peer educators are used to discuss family planning and contraceptive use with women using the clinic. The evaluators follow up with the participants one year later to record contraceptive use and whether any unwanted pregnancies occurred. There is no comparison group, so evaluators are looking only at the group that received the counseling. They find that since receiving counseling the rate of birth control usage has increased significantly. However, the evaluators are aware that last year a regulation was put in place providing free birth control to women regardless of insurance status.