The Strengths and Difficulties Questionnaire (SDQ) (Goodman, 2007) is a 25-item screening questionnaire for children aged 3- 16 years that screens for difficulties in four areas; emotional symptoms, conduct problems, hyperactivity/ inattention and peer relationship problems in addition to strengths in prosocial behavior. Goodman’s inclusion of these scales is based on a factor analysis of an expanded version of the Rutter Parent Questionnaire (Elander & Rutter, 1996) (Goodman, 2004). Goodman (2007) aimed to develop a tool that reflected contemporary concerns (e.g. prosocial behavior, concentration), could be administered as both a multi informant instrument and as a self- report instrument and could be one page in length. The instrument was originally developed in the United Kingdom. Norms for Australia are readily available on the sdq.com website. Australian norms have also recently been developed for children aged 4 to 6 years (Kremer et al., 2015)
The SDQ scores are based on informant reports from parents and teachers for younger children and self- report measure for adolescents aged 11- 16 years of age (Goodman et al., 1998). An extended version is available that assesses the impact of difficulties in terms of chronicitiy, distress, social impairment and burden on others (Goodman & Soctt, 1999). A further version of the SDQ is available that includes two additional questions measuring the impact of the intervention. It has been found to be a useful outcome measure of Australian CAMHS services (Mathai, Anderson & Bourne, 2003).
The SDQ was initially tested against the Rutter Parent Questionnaire and found to have good concurrent validity. The SDQ is generally considered to have acceptable reliability and validity. The teacher version of the SDQ has been found to have high internal consistency with Cronbach’s alpha coefficients ranging from .70 (Peer Problems) to .88 (Hyperactivity/ Inattention) (Goodman, 2001). The reliability for the parent rated scales ranges from .57 (peer problems and prosocial behavior) to .84 (hyperactivity/ inattention (Goodman, 2001). The SDQ has been shown to be significantly better than the Child Behaviour Checklist (CBCL) at detecting inattention and hyperactivity and as good as the CBCL at detecting internalizing and externalizing problems (Goodman & Scott, 1999). SDQ assessments have been found to correlate to a moderate to high level with clinician diagnoses in both a community and a clinical sample (Mellor, 2005).
While reliability and validity are generally considered to be acceptable a recent systematic review of the psychometric properties of the SDQ (Kersten et al., 2016) concluded that the SDQ can be used to compare groups but does not have adequate sensitivity for clinical decision making. Further, agreement between informants has been found to be low (.24 to .45) (Kersten et al., 2016). The discriminant ability of parent and teachers versions in detecting mental health problems is better in clinical samples than in community samples (Stone, Otten, Engels, Vermulst & Jannsens, 2010).
The SDQ is available in over 60 languages (sdq.org) including Auslan (Cornes & Broqn, 2015). A recent study (Williamson et al., 2014) noted that while the SDQ is appropriate for Aboriginal children living in an urban environment there were some aspects of the questionnaire that could be improved (e.g. the wording of some items and little focus on community connectedness). The SDQ can be used as a screening tool in a range of settings, for research and to measure the impact of an intervention. The instrument asks informants to base their ratings on the past six months. Each item is scored on a 3-point ordinal scale where 0=not true, 1= somewhat true and 2= certainly true. Scores for scales 1- 4 are summed to provide a total difficulties score. Children are categorized as being in one of three score ranges; within the normal range (< 80th percentile), within the borderline range (90-90th percentile) and within the clinically significant range (>90th percentile). Scoring templates and computerized scoring is available from the SDQ website www.sdq.org. Australian norms are available on the sdq website.
References
Cornes, A. J. & Broqn, M. P. (2012). Mental health of Australian deaf adolescents: An investigation using an Auslan version of the strengths and difficulties questionnaire, Deafness and Educational International, 14, 161- 175
Elander, J., & Rutter, M. (1996). Use and development of the Rutter Parents’ and Teachers’ Scales. International Journal of Methods in Psychiatric Research, 6, 63-78.
Goodman, R. (1994). A modified version of the Rutter parent questionnaire including items on children’s strengths: A research note. Journal of Child Psychology and Psychiatry, 35, 1483-1494.
Goodman R (1997) The Strengths and Difficulties Questionnaire: A Research Note. Journal of Child Psychology and Psychiatry, 38, 581-586.
Goodman, R. (2001). Psychometric properties of the strengths and difficulties questionnaire. Journal of The American Academy of Child and Adolescent Psychiatry, 40(11), 1337–1345.
Goodman, R., Meltzer, H., & Bailey, V. (1998). The Strengths and Difficulties Questionnaire: A pilot study on the validity of the self-report version. European Child & Adolescent Psychiatry, 7(3), 125–130.
Goodman, R. (1999). The extended version of the Strengths and Difficulties Questionnaire as a guide to child psychiatric caseness and consequent burden. Journal of Child Psychology and Psychiatry and Allied Disciplines, 40(5), 791–799.
Kersten, P., Czuba, K., Mc Pherson. K., Dudley, M., Elder, H., Tauroa, R. & Vandal, A. (2016). A systematic review of evidence for the psychometric properties of the Strengths and Difficulties Questionnaire, International Jounral of Behavioral Development, 40, 64-75
Kremer, P., De Silva, A., Cleary, J., Santoro, G., Weston, K., Steele, E. Nolan, T. & Waters, E. (2015). Normative data for the Strengths and Difficulties Questionnaire for young children in Australia, Journal of Peadiatrics and Child Health, 51, 970-975
Mathai, J., Anderson, P., & Bourne, A. (2003). Use of the Strengths and Difficulties Questionnaire as an outcome measure in a child and adolescent mental health service. Australasian Psychiatry, 11(3), 334–337.
Mellor, D. (2005). Normative data for the strengths and difficulties questionnaire in Australia. Australian Psychologist. 40, 215–22.
Stone, L.L., Otten, R., Engels, R., Vermulst, A.A., Janssens, J.M. (2010) Psychometric properties of the parent and teacher versions of the strengths and difficulties questionnaire for 4-to 12-year-olds: a review. Clinical child and family psychology review 13: 254–274. doi: 10.1007/s10567-010-0071-2
Williamson, A., McElduff, P., Dadds, M., D’Este, C., Redman, S., Raphael, B., Daniels, J. & Eades, S. (2014). The construct validity of the Strengths and Difficulties Questionnaire for Aboriginal children living in urban New South Wales Australia, Australian Psychologist 49, 163- 170.