Aims: To research the link between personality factors, stress and Coronary Heart Disease (CHD)
Procedure: In a nine year longitudinal study, 3,000 healthy men between ages 39-59 were assessed to determine their personality type, and then followed up throughout the nine year longitudinal study. The men were split into two roughly equal groups, depending on whether they were assessed as Type A or non-Type A. Type A individuals tended to be ambitious, competetive, time-conscious and demanding of perfection. Non-Type A individuals were more relaxed and easy-going.
Findings: Over the course of the study, 70% of the 257 men who died were from the Type A group.
Conclusion: People who are of Type-A are more susceptible to stress because of their behaviour traits, and are consequently more likely to suffer stress related illness such as CHD.
Strength: The study showed a strong correlation which suggests that there is a link between "personality type" as assessed by F+R.
Weakness 1: Correlation isn't the same as cause-effect. While it could be the case that Type-A behaviour leads to increased CHD risk, it could also be the case that the behaviour and CHD are themselves caused by a separate unknown factor.
Weakness 2: The classification into Type-A and non Type-A may be simplistic: individuals exhibit different behaviours in different situations and times, and so a Type-A individual might actually be assessed as non Type-A if re-assessed on a different occasion.