Matt N. Williams

Justify your alpha

In response to recommendations to redefine statistical significance to P ≤ 0.005, we propose that researchers should transparently report and justify all choices they make when designing a study, including the alpha level.

Validating a measure of children's monitoring-blunting coping styles in dental situations

The monitoring-blunting theory of coping suggests that when faced with a threatening situation, individuals can respond by either monitoring or avoiding (blunting) threatening information. The current study sought to validate a scale of childrens preferences for monitoring or blunting in dental situations (the Monitoring Blunting Dental Scale or MBDS). The psychometric characteristics of the scale were assessed in a sample of 240 New Zealand children aged 11–13. Reliability was adequate for both monitoring (α = 0.74) and blunting (α = 0.76) subscale scores. Convergent validity was indicated by strong correlations (>0.6) between the measures subscales and those of a related scale, although discriminant validity with respect to dental anxiety was problematic for the blunting subscale. Exploratory factor analysis supported a two-factor monitoring-blunting model, although confirmatory factor analysis indicated reasonable but imperfect fit for this model, SBχ2(251) = 510.7, p < 0.001, RMSEA = 0.066. We reflect on conceptual issues which may underlie the difficulties experienced here and elsewhere in developing psychometrically sound measures of Millers blunting construct and suggest that the monitoring subscale of the study scale may be most useful to other researchers.

What Makes for the Most Intense Regrets? Comparing the Effects of Several Theoretical Predictors of Regret Intensity

Several theories have been proposed to account for variation in the intensity of life regrets. Variables hypothesized to affect the intensity of regret include: whether the regretted decision was an action or an inaction, the degree to which the decision was justified, and the life domain of the regret. No previous study has compared the effects of these key predictors in a single model in order to identify which are most strongly associated with the intensity of life regret. In this study, respondents (N = 500) to a postal survey answered questions concerning the nature of their greatest life regret. A Bayesian regression analysis suggested that regret intensity was greater for—in order of importance—decisions that breached participants’ personal life rules, decisions in social life domains than non-social domains, and decisions that lacked an explicit justification. Although regrets of inaction were more frequent than regrets of action, regrets relating to actions were slightly more intense.

Do hotter temperatures increase the incidence of self-harm hospitalisations?

A relationship between air temperature and the incidence of suicide has been established in a number of previous studies. Interestingly, the relationship between geographical variation in temperature and suicide incidence has generally been found to be negative, while the relationship between temporal variation in temperature and suicide incidence has generally been found to be positive. It is less clear, however, how temperature relates to the incidence of self-harm. This topic is of particular importance given the presence of ongoing global warming. This study investigated the relationship between temperature and the incidence of self-harm resulting in hospitalisation in New Zealand. Self-harm hospitalisations by date and district for 1993–2009 were obtained from the Ministry of Health. Meteorological data was obtained from NIWA. Generalised linear mixed models were used to estimate the effects of three different components of variation in temperature: geographical, seasonal and irregular. Irregular (random) daily variation in temperature had a modest positive relationship with the incidence of acts of self-harm resulting in hospitalisation, with about 0.7% extra incidents for every 1 °C increase in temperature. However, there was no strong evidence for a positive effect of either seasonal or geographical variation in temperature. We conclude that temperature does appear to bear some relation to the incidence of self-harm, with irregular daily variation in temperature having a positive effect. However, inconsistencies in the effects of different components of variation in temperature make it challenging to accurately predict how global warming will influence the incidence of self-harm.

Using Bayes Factors to Test Hypotheses in Developmental Research

This article discusses the concept of Bayes factors as inferential tools that can serve as an alternative to null hypothesis significance testing in the day-to-day work of developmental researchers. A Bayes factor indicates the degree to which data observed should increase (or decrease) the credibility of one hypothesis in comparison to another. Bayes factor analyses can be used to compare many types of models but are particularly helpful when comparing a point null hypothesis to a directional or nondirectional alternative hypothesis. A key advantage of this approach is that a Bayes factor analysis makes it clear when a set of observed data is more consistent with the null hypothesis than the alternative. Bayes factor alternatives to common tests used by developmental psychologists are available in easy-to-use software. However, we note that analysis using Bayes factors is a less general approach than Bayesian estimation/modeling, and is not the right tool for every research question.

The Psychometric Properties of a Brief Version of the Systemizing Quotient

The construct of systemizing – the drive to construct or understand systems – has an important role in the Extreme Male Brain theory of autism. While a brief version of the Systemizing Quotient (SQ) has been proposed, there is a need to assess its psychometric properties. This study assessed factorial and construct validity of an 8-item version of the SQ on a sample of 627 participants. A single-factor latent variable model with a single correlated error term showed adequate fit in a confirmatory factor analysis. This model also demonstrated metric invariance across genders when controlling for an effect of age on item responses. Reliability was acceptable, &agr; = .72. As further evidence for construct validity, SQ scores showed expected relationships with mental rotation performance, trait anxiety, childhood extroversion, childhood agreeableness, and gender. Overall, the results indicated good psychometric properties for the brief version of the SQ, suggesting that this scale could be useful when researchers require a systemizing measure that is minimally burdensome to complete.

In response to "Temperature and violent crime in Dallas, Texas: Relationships and implications of climate change"

The online version of this article is published within an Open Access environment subject to the conditions of the Creative Commons Attribution-NonCommercial 4.0 License http://creativecommons.org/licenses/by-nc/4.0/.