This is an independent measurements design, which aims to determine the height of the preferred partner between two groups of participants: male and female. The independent variables were participants' gender and their respective heights. The dependent variable was the partner's preferred height, the acceptable height range for a partner, as well as satisfaction with the partner's height and partner height differences. The study involved participants being voluntarily recruited to respond to a short survey and provide basic socio-demographic information. This research study should be classified as a quasi-experiment, since the independent variable (height and gender) is not manipulated by the researcher but occurs naturally. A true experimental design would involve a single group, with a common measured outcome and randomly assigned participants. In this way, individual background variables such as gender do not meet the requirements to be a true experiment since gender cannot be intentionally manipulated in this way. Furthermore, participants were not randomly selected from the general population; instead all participants were first-year psychology students at a large European university who participated in exchange for course credits. A threat to selection validity has already been addressed in this study by including only heterosexual individuals. The reasoning behind this may be that homosexual participants would approach the survey with respect to their own sexual orientation preferences; therefore the answers provided by this group could vary or be more inconsistent than the rest of the sample group studied, as no studies have been conducted on homosexual height preferences compared to their own. Therefore they were excluded. In practice it would just ask them their sexual orientation and not include their answers in the final results, while still allowing them to get course credit. These participants should be informed of the purpose of this study and allowed to withdraw from the survey as their survey responses would not be included. Ethically, patients with same-sex preferences may not want their relationship preference or status known; so confidentiality remains a small but important potential issue. Furthermore, the participant's self-assessment of height is a potential limitation of the test, although reference is made in this paper to the fact that self-assessment of height is relatively reliable. In most cases, an overestimation of the participant's height was expected. Similarly, accuracy in assessing partners' height has been found to be imprecise, most often reporting a rounded number ending in 0 or 5.