First, between family designs pools all individuals of a certain birth position and compares them to all of the individuals of another birth position. One major issue associated with this design strategy is that it fails to account for between family differences like family size, socioeconomic situation, and personal background information (Sulloway, 1999). Because wealthy families tend to have smaller family sizes, later born children are less likely to come from these families than oldest or only children which is why Ernst and Angst (1983) determined that uses between family designs may be the contributing to false findings of birth order effects (as cited in Marini & Kurtz, 2011). …show more content…
In this type of design participants will evaluate their siblings and themselves on various personality traits being measured (Healey & Ellis, 2007). By using this system of design involving making these direct comparisons between siblings of the same family, Sulloway (1999) believed that overall differences would be much more evident. However, Marini and Kurtz (2011) argue that personality differences may only be experienced within the home environment. In other words, within family studies lack external