The aim of Study 1 was to develop the KIPS, a novel multidimensional parent-report measure of the important domains contributing to behavioural insomnia in children aged 3–12 years. As noted above, it is important for clinicians to both obtain specific information around the child’s sleep patterns and problems and to conceptualise the child’s sleep problem(s) by determining factors underpinning and contributing to them. The KIPS therefore comprises two sections, 1) a more general sleep and bedtime information section and 2) a psychometric measure of six theoretically derived factors that underlie and contribute to, child sleep problems. In this way, the KIPS is similar to other measures developed for both clinical and research purposes such as the Child Behaviour Checklist (CBCL; Achenbach, 1991) and the Eating Disorder Inventory (EDI; Garner, 2004; Garner et al., 1983).
Section 1: Specific Sleep Information. Section 1 included three sub-sections: sleep diary information, sleep hygiene behaviours, and parasomnias / respiratory problems. Although important for clinicians to assess, sleep diary information (e.g., sleep and wake times, naps, wakings during the night etc) was not possible (or appropriate) to include in Section 2 (the psychometric questionnaire), and therefore was included in Section 1. Similarly, sleep hygiene information is critical for clinicians to gather, yet the behaviours are very specific, do not tend to co-occur, and therefore do not ‘hang together’ as a subscale. As such, sleep hygiene items were included in Section 1 rather than Section 2. Finally, given that parasomnias and respiratory difficulties require different psychological interventions to those considered standard for behavioural insomnia, and/or indeed may require medical intervention, the presence of parasomnias and respiratory issues was also screened for in Section 1.
Section 2: Psychometric Measure. Section 2 consisted of the psychometric measure that is the focus of this paper. It included 6 factors that, from a cognitive-behavioural perspective, are thought to underly and / or contribute to, sleep problems in children: Bedtime Routines, Bedtime Fears, Bedtime Worries, Bedtime Resistance, Sleep Maintenance Problems, and Co-Sleeping Behaviours. It was hypothesised that the exploratory factor analysis (EFA) of these items would produce 6 factors corresponding to the 6 constructs.
Study 1 Method
Participants
The participants were 328 men and women aged between 18 and 56 years (M = 36.47, SD = 5.85), who reported being either the mother (95.4%), father (2.7%), grandparent (0.3%) or caregiver (1.5%) of a child aged between 3 and 12 years. Another 34 participants began the questionnaire but were excluded due to obviously erroneous data entry, failure to consent, or having children outside the selected age range. Supplementary Tables 1 and 2 report detailed demographic information for parents and children respectively. Of the participants, 10.7% were university students, 37.2% reported a bachelor degree as their highest level of education, 46% reported a household income between $100,001 and $200,000, 78.3% were employed full time or part time, and 89.9% were Australian Caucasian. Of the participants in the sample, 55.2% reported having a child aged 3–5 years. Most participants (97.9%) reported having a child without any formal mental health, sleep or developmental diagnosis. Of the sample, 30.2%, 8.2% and 6% of the sample believed that their child had a mild, moderate and severe sleep problem respectively.
Measures
Caregiver Demographics. Participants were asked a series of single item demographic questions relating to their gender, age, level of education, marital status, household income, ethnicity, and relationship to the child.
Child Demographics. Participants were asked a series of demographic questions relating to the child’s age, ethnicity, family structure and caregiver arrangements, number of siblings, and the presence of any formal diagnoses.
Self-Reported Sleep Problems. Participants were asked to rate (irrespective of any formal diagnosis) whether they felt their child suffered with a sleep related problem. Participants indicated their answer on a four-point Likert-type scale, where 0 = no problem, 1 = mild problem, 2 = moderate problem, and 3 = severe problem.
The KIPS Measure.Section 1: Specific Sleep Information. As noted above, Section 1 of the KIPS included 3 sections assessing sleep diary information, sleep hygiene, and the presence of parasomnias / respiratory issues. With respect to sleep diary information, Section 1 required parents to consider the past week, and to indicate their child’s usual wake time, bed-time, and time they fall asleep on both weekdays and weekends. It also required them to report on the frequency and duration of night awakenings, and the frequency and duration of daytime naps. With respect to sleep hygiene information, parents were asked to consider the past week, and to indicate how true each of 8 items (assessing use of screens, hunger / fullness before bed, use of bed for play, rough and tumble play before bed, consistent bed time / wake time, caffeinated food and drink in the late afternoon / evening), were for their child on a 6-point scale from 0 (never true) to 5 (always true). In terms of screening questions for parasomnias and respiratory problems, parents were asked to consider their child’s sleep over the past week, and indicate how true they thought each of 6 statements (my child wakes in the night with panic or fear from a nightmare/night terror; my child has nightmares; my child wets the bed; my child snores loudly; my child stops breathing/snorts/gasps in their sleep; my child sleepwalks) were for their child on a six-point scale from 0 (never true) to 5 (always true).
Section 2: Psychometric Questionnaire. Items for Section 2 of the KIPS were generated from a comprehensive review of the paediatric sleep literature as well as consultation with experts in child sleep and anxiety (clinical and research experts), and a critical review of existing scales. A scale blueprint (i.e., the hypothesized factor structure) was created and served as a framework for item creation (Rust & Golombok, 2014). Items were then created specifically to tap each content area (i.e., factor). An initial 44 items were developed to address six key content areas (i.e., Bedtime Routines [5 items], Bedtime Fears [8 items], Bedtime Worries [5 items], Bedtime Resistance and/ or Oppositional Bedtime Behaviour [12 items], Sleep Maintenance Problems [7 items] and Co-Sleeping Behaviour [7 items]).
Items (for both sections of the KIPS) were written to avoid double-barrelled questions and complex wording, and included a mix of positively and negatively worded items. Insurance against ambiguity of items and indecisiveness, acquiescence and social desirability were tackled at the item development and expert review stages. The expert panel, consisting of 7 researchers from the USA and Australia, who had published scales or other research in paediatric mental health, were consulted on the six content areas and the appropriateness of items generated for each content area, including item phrasing. Clark and Watson (2019) suggest erring on the side of over-inclusiveness when generating initial items, and to rely on the subsequent psychometric analysis to identify weak or unrelated items. For this reason, items that were unanimously identified as being problematic, were deleted at the expert review stage, and other problematic items were flagged for review in the psychometric stages.
The instructions for the scale were as follows; “Below is a series of statements that describe a range of bedtime and sleep related behaviours your child might demonstrate. We would like you to think about your child and their behaviour over the pastweekwhen responding to the questions below. If there was a reason that the last week was unusual (such as your child was unwell or there was a holiday period), respond to the questions based on a typical week. Please think about the following statements in relation toyour child and household, and rate how true each of the following statements are, using the following scale:” The six-point scale ranged from 0 (never true), to 5 (always true), and subscale items were summed so that higher scores reflected greater sleep related difficulties. Thus, the asterisked items displayed in Table 1 are reverse scored before summing. A total score was obtained by summing the KIPS subscale scores.
Procedure
Approval for the study was granted by the BLINDED FOR REVIEW University Human Ethics Review Committee (HREC: 2019/785). All student participants were recruited through the psychology student subject pool, and all non-students were recruited through the university email call for research volunteers, and via social networking sites (e.g., Facebook). Recruitment material informed potential participants of eligibility criteria for participation (i.e., a primary caregiver of a child aged between 3 and 12 years) and provided a web link that directed them to the online survey hosted on Qualtrics. After clicking on the link, individuals were directed to a downloadable information sheet and consent form that outlined the purpose of the study, participation requirements, and confidentiality. The information sheet informed participants that the research was being conducted to develop a new measure of child sleep related problems, and that they would be asked to answer a series of questions related to child sleep, family life, and personal experiences as a parent. Participants were then instructed to indicate, via radio buttons, that they had read the information and consent forms and consented to participate in the research. Only those who provided informed consent went on to complete the questionnaire battery. Following completion of the questionnaire, participants were invited to enter their name into a draw to win one of ten $50 gift vouchers (non-students) or gain course credit (students) for their participation.
Study 1 Results
Preliminary Analyses
Barlett’s test of sphericity was significant (χ2 = 6053.34, df = 378, p < .001) and the Kaiser–Meyer–Olkin value was .90, indicating that the initial 44 KIPS items were appropriate for factor analysis. Additionally, all measures of sampling adequacy taken from the diagonal of the anti-image correlation table were = > .80.
Exploratory Factor Analysis
Prior to exploratory factor analysis (EFA), items were removed if they met two or more of the following criteria: 1) item redundancy or insufficient correlations with other items (i.e., inter-item correlations of r > .8 or < .2 respectively), 2) poor item statistics (i.e., if all response options were not utilized), and 3) age bias (i.e., if a singular item correlated (r > .35) with the reported age of the parent (Clark & Watson, 1995; Rust & Golombok, 2014). As a result, 11 items were excluded from further analyses, leaving 33 items for the EFA.
The first EFA resulted in the extraction of six factors with eigenvalues greater than 1 (i.e., 11.32, 3.33, 2.98, 2.63, 1.59, and 1.42 respectively). Parallel analysis revealed 15 eigenvalues greater than 1, the first six of which (i.e., 1.65, 1.56, 1.49, 1.44, 1.39, and 1.35 respectively) were smaller than those extracted through EFA (O’Connor, 2000). Inspection of the scree plot revealed an inflection point between 6 and 7 factors. Thus, results converged on a 6-factor structure. Inspection of the pattern matrix revealed that all factors aligned with the hypothesised blueprint.
Items loading on the six factors were evaluated for deletion against the following criteria; 1) poor factor loadings (i.e., loadings < .40) or small communalities (i.e., < .40), 2) cross-loadings on two or more factors (i.e., loadings > .3 on the second factor), 3) a lack of conceptual/face validity (i.e., if the loading of an item on a factor did not align with theory or the designed blueprint), and 4) constitution of part of a non-robust factor (i.e., a factor with < 3 items; Clark & Watson, 1995; Comrey, 1988; Floyd & Widaman, 1995; Guttman, 1954; Rust & Golombok, 2014). Subsequently, 8 items were removed, resulting in a final set of 25 items.
In a final EFA of the 25 items (see Table 1), six factors had eigenvalues greater than 1 and explained 73.4% of the variance in the items. The final items, factor loadings, and scale statistics are presented in Table 3. The factors were labelled; Sleep Maintenance Problems (4 items), Co-Sleeping Behaviours (4 items), Bedtime Routines (5 items), Bedtime Resistance (5 items), Bedtime Worries (3 items) and Bedtime Fears (4 items). Factor 1, Sleep Maintenance Problems, had an eigenvalue of 8.16 and accounted for 32.65% of the variance in the items. The four items loading highly onto this factor reflected the extent to which children have difficulty putting themselves back to sleep after waking and had loadings that ranged from .83 to .51. Factor 2, Co-Sleeping Behaviours, contained four items reflecting the extent to which parents and children engage in co-sleeping at night, with loadings ranging from .95 to .72. The five items loading onto Factor 3, Bedtime Routines, ranged from .85 to .55 and reflected the extent to which families consistently engage in a bedtime routine. Factor 4, Bedtime Resistance, contained five items reflecting the extent to which children exhibit oppositional behaviour at bedtime and resist the bedtime process, with item loadings ranging from .84 to .69. The three items loading onto Factor 5, Bedtime Worries, reflected the extent to which children’s worries interfere with sleep, with loadings ranging from .87 to .69. Finally, Factor 6, Bedtime Fears, contained four items reflecting the extent to which children demonstrate night-time related fears, with loadings ranging from .86 to .61. All factors were significantly correlated with each other (r’s ranged from .11 to .52). Cronbach’s alphas were acceptable to high for all subscales (α’s of .88, .93, .82, .88, .85, and .86 respectively for Factors 1–6) and Cronbach’s alpha for the total composite score was high (α = .91).