heston - adoption study

• example of adoption study

  heston (1966)
• heston - who were the participants?

  • born to SZ mothers in an american psychiatric hospital
  • children were selected if mothers had put them up for adoption from birth - researches ensured the mother had a diagnosis of SZ and no diseases
• heston - how many participants?

  58 participants chosen and matched with a control group on sex, type of eventual placement and length of time in care
• heston - how was data collected?

  several sources e.g: hospital, school and police records, interviews from friends
• heston - how was information evaluated?

  • 2 psychiatrists evaluated information on each participants blindly and independently
  • third evaluation by heston
  • diagnosis of SZ only given when all raters agreed
• heston - what were the findings?

  rate of SZ in those born to schizophrenic individuals was 10.6% compared to 0% in those not born to schizophrenic individuals
• strength of heston

  • matched design
  • e.g: controlling gender, length of time in care - minimised participant variables that could have affected internal validity of results
  • therefore, can be confident that it is biological inheritance which caused differences not environmental factors e.g: time in care
• weakness of heston

  • not all factors were controlled
  • e.g: psychiatric status of father was not checked
  • cannot be sure if this contributed to participants results
• weakness of heston

  • secondary data
  • e.g: hospital records collected which could be interpreted subjectively
  • someone could think a patient is schizophrenic even if notes dont say this
• strength of heston

  • heston established inter-rater reliability
  • when analysing patient records by using multiple data sources and 3 different raters
  • this provides a reliable interpretation of notes as they were determined to have SZ if they have all agreed