Validity of the Danish the parental Stress Scale (PSS): Psychometric properties addressed using item response theory emphasizing differential item functioning

Background: Parental stress poses a risk on child and adolescent development, mental health, and well-being. Research on the consequences of parental stress and how families can be helped is therefore important. There is a need for a valid measurement tool to measure parental stress.
The Parental Stress Scale (PSS) has been translated into Danish and has already been used in research and practice. The PSS has the following assets: 1) it is short (18 items) which makes it less demanding for respondents, 2) it is available for free and 3) It can be used with parents of children aged 0-18 years.
Based on international validity studies the scale seems to be a promising measurement tool. The scale has, however never been validated in a Danish context, i.e. whether it measures parental stress and whether it functions equally in different subgroups of parents.
Aim: to investigate the construct validity of the Danish translation of the Parental Stress Scale and the psychometric properties of the instrument with emphasis on differential item functioning. The project is divided into three sub-projects with the following research questions: 1) Is the PSS valid when used with a relatively representative community sample of mothers of infants (0-1 years old)?, 2) Is the PSS valid when used with parents of children and adolescents (1-18 years old) with and without known difficulties or diagnosis (non-vulnerable and vulnerable groups)? and 3) Do parent couples experience parental stress symptoms to the same degree, and are the findings heterogeneous or homogeneous dependent on the difficulties or diagnosis of their children?
Sample and methods:
The validation study is primarily based on already collected data from other projects. In addition, data from a relatively representative sample of Danish parents will be collected. Data cover an age span of 0-18 year-olds and comprise data from parent couples and parents to children with and without difficulties/diagnoses, respectively.
The psychometric properties of the scale will be tested using Rasch models (RM). The concordance with regard to specific symptoms of parental stress between the parents will be tested using tests for marginal homogeneity
Perspectives: Data and the use of RM make it possible to conduct a very thorough validation of PSS. The validation will provide knowledge on many aspects of the use of PSS in a Danish context. This knowledge will benefit research and practice in Denmark.