Generalizability of Adoption Studies

How the probands are recruited also can affect the quality of a study’s conclusions. One potential source of bias is the influence of environmental factors on the selection of proband adoptees in the adoptees’ family method. For example, psychological or social problems in an adoptive family may contribute to the adoptee’s psychopathology. Simultaneously, these problems may prompt the family and the adoptee to seek more treatment and thus increase their chances of being included in a sample of adoptees recruited from a clinic population. Factors such as these may compromise the representativeness of the sample. Similarly, refusal rates among potential study participants could influence the quality of the data obtained. For example, it is possible that adoptees and their families who refuse to partici­ pate in a study as a group are distinguished by certain qualities (e.g., personality characteristics). Consequently, their refusal could reduce the representativeness of the study sample.