Hoefelmann et al. (2006) Study

• Aims

  - To investigate factors affecting sleep in high school students. It aimed to investigate the effects of life style factors on the quality of sleep in high school students, in order to verify that the two are associated.
• Procedure

  - Students answered a questionnaire

  - Sleep quality was measured by the question "How often do you think you sleep well?" 'Always' and 'almost always' counted as positive , 'sometimes', 'almost never' or 'never' counted as negative.

  - Sleep duration measured by the question "How many hours do you sleep per day?" > 8 hours counted as enough sleep, < 8 hours counted as not enough sleep.

  - lifestyle factors were measured through the number of times exercised, time spent watching tv, and how many soft drinks snacks consumed.
• Results

  - students who don't exercise, often ate snacks and watched lots of TV were less likely to report short sleep duration.

  - Students who played excessive hours of computer games were more likely to say they did not get enough sleep.

  - 5/10 had poor sleep quality

  -8/10 not enough sleep

  -these figures didn't change in longitudinal

  - frequency of physical activity was associated with poor sleep quality
• Conclusion

  if perceived quality and duration of sleep was poor, it is unlikely that will change over time, some behaviours can be associated with sleep quality and duration
• Evaluations- Graves

  This study had a large sample, representative of teenagers in Brazil, however, this study had participants originating only in Brazil, South America. Therefore, it cannot be generalized to all teenagers across the world, who may be exposed to different cultures (around sleeping patterns), environments and light outside.
• Evaluations- gRaves

  The same questionnaire was used first and then in the follow up study 9 months later. This shows standardized procedures and consistency, which makes it reliable. However, there is the possibility of order effects and demand characteristics with any repeated measures design. This means that as the students have to complete the same measure again, they may become tired and/or guess the aim of the study, which impacts the validity of results
• Evaluations- grAves

  The major strength of this study is that the findings have major implications on the general health of teenagers and young people in South America. Young people now know how to improve their sleep, and sleep deprivation can result in mental and physical illness.
• Evaluations- graVes

  A randomized control trial randomly assigns participants into either the control or experimental group. Random allocation in a psychological sample that has many participants are likely to be an unbiased, representative sample of society. However, as is the case with any self report questionnaire, there is a large problem with honesty. Participants may not answer honestly and therefore the result is an invalid result, this could be down to social desirability.
• Evaluations- gravEs

  We can presume that there mostly was informed consent from all participants who were over the age of 16. Any individuals who were under 18 had an older adult confirm consent. Also, handing out a questionnaire that is voluntary is an ethical way to obtain data easily whilst students were at school or college. Negative consent was obtained from parents in the study, making the study ethically questionable. This means that children under 18 completed it, their parents may not have been aware
• Sample

  number: 989

  age: 14-24

  nationality: Brazilian

  occupation: students