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August 23, 2012

Ways to improve peer-nominations.



Marks, P.E.L., Babcock, B., Cillessen,A.H.N., & Crick, N.R. (in press). The effects of participation rate on the internal reliability of peer nomination measures. Social Development.

This is a summary on a topic which is most relevant to those people who are actually trying to collect data on peer-aggression and peer-victimization. The article is one which has been accepted for publication, but has not as yet been published.

The focus here is on whether peer-nominations are reliable ways to assess the social behaviours and relationships of children. Self-reports are often used for these purposes, but t has been argued that these are subject to biases which may make us question their reliability. For example, people may be unwilling to admit to bullying others but may be all to ready to report that they themselves intervene when they see others being bullied. There are also other statistical issues relating to shared-method variance that are important (I won’t go into these here, but see here for more information). So, researchers often use peer-nominations instead, on the understanding that children and young people will more honestly report on what their peers are like than what they themselves are like.

However – peer nomination procedures are, of course, based on getting reports from peers. And when we conduct research we rarely get 100% participation rates. So the question here is whether participation rates influence how reliable the peer nomination are. Put another way, are these measures poor ways to assess children and young people’s social behaviours and relationships if too few students choose to take part in a research study?

These researchers recruited 642 young people aged approximately 10-11 years old from 10 elementary schools in the USA. They collected peer nominations of friendship, liking/ peer acceptance, popularity, overt aggression, and prosocial behaviour.

Not surprisingly, reliability (Cronbach’s alpha) was higher when participation was higher. However, overt aggression and prosocial behaviour were the most reliable, and liking and friendship were the least reliable. The authors muse over whether this is to do with the difference between observable concrete behaviours (e.g. hitting someone) and things that require much more personal judgement (whether someone is a friend or not). I’d add to this that if this line of reasoning is correct, then it may be the case that indirect aggression is less reliable than overt aggression since indirect aggression can be less obvious to observers.

The authors also note that asking for unlimited nominations, rather than say a ‘top-3’ most aggressive peers, is best. In addition, having more nominations (e.g. two peer nomination items assessing prosocial behaviour rather than one) was also associated with greater reliability.

Based on the authors’ expertise as well as their results, they suggest that participation rates of 40% may be sufficient for good reliability relating to measurement of overt aggression and prosocial behaviour. However, for friendships reliability could be problematic even when participation rates were over 85%. Perhaps friendships need to be operationalized in terms of specific behaviours and this could help to improve reliability.  

August 20, 2012

More free articles

I've just learned about a journal called the Journal of School Violence which I wasn't really aware of before. They publish lots relating to bullying (obviously!) and have open-access editions from time to time. The most recent of these can be accessed here, though there are more in the back issues of you search further back.

August 16, 2012

Quality, not just presence, of friendships important for reducing bullying and peer-victimization


Kendrick, K., Jutengren, G., & Stattin, H. (2012). The protective role of supportive friends against bullying perpetration and victimization. Journal of Adolescence, 35, 1069-1080.

This study aimed to build on a literature which examines the “Friendship protection hypothesis.” This is the theory that having friends can prevent negative experiences and therefore also prevent the negative outcomes associated with those experiences. They note that both quality of friendships and quantity of friendships may be important regarding whether or not young people experience peer-victimization.

The primary aim, as stated by the authors, was to address an issue which has received little prior attention, namely the short-term (across one-year) relationships between perceived support from friends and links to both bullying and victimization. These authors also looked at whether depression and engaging in property crimes were also related to bullying and victimization. They looked at these issues because they have both been associated with bullying and victimization in previous research.

The authors recruited 980 (435 boys) young people aged between 12 and 16 years old in Sweden. All young people completed self-report measures of bullying, victimization, friendship quality, depression, and involvement in property crime. These measures were all completed at two different points in time, and the time points were one year apart. This is called a cross-lagged research design and allows the researchers to unpick which of these issues leads to the other(s).

Using a statistical technique called structural equation modelling, Kendrick and her colleagues found that:
  • Young people who felt that they had a supportive friendship friend support at Time 1 reported lower levels of victimization at Time 2; for boys, supportive friendships also led to lower levels of bullying of others. 
  • Bullying of others at Time 1 predicted property crime at Time 2, but this was true only for girls. Being involved with bullying of other may therefore be indicative of a more serious downward spiral in the behaviour of girls than for boys.
  • Victimization at Time 1 predicted depression at Time 2. Depression at Time 1 predicted victimization at Time 2 for boys only (perhaps less tolerated among boys and so they are picked on?). This supports previous work that suggests there is a vicious circle taking place here, that is to say, victimization leads to higher symptoms of depression which in turn lead to higher levels of victimization and so on.
  • Victimization at Time 1 did not predict levels of friend support or property crimes at Time 2.
  • Depression at Time 1 does not predict bullying at Time 2.


The authors conclude that friendship may protect adolescents from being victimized because such friendships increasing their psychological wellbeing, and that this in turn may reduce their vulnerability to aggression from peers. They also note that supportive friends may actually act directly as defenders, and in this way may provide practical help as well as emotional support.

It is worth noting that most of the effect sizes throughout this paper were fairly small. This means that the effects of, e.g. victimization upon depression across the year of the study, were not large. While some previous studies have reported larger effects, I would say that the cross-lagged design of this study (which takes into account that fact that the best predictor of e.g. depression at Time 2 is depression at Time 1) will provide more realistic estimates of these effects that a simple cross-sectional design does.