The MCHAT (Modified Checklist for Autism in Toddlers) was developed as a Level 1 screening tool for autism/PDD to be given to all children at their 18-24 month pediatric visit. Physicians do not need to be on hand as the parent fills out the checklist. Children who fail the MCHAT should be given a followup phone interview before referral for diagnostic evaluation. The MCHAT relies on parent reports of current skills and behaviors rather than the physician's observation of the child.
The checklist is composed of the first 9 items from the CHAT and 21 new items that were designed to broaden the checklist symptoms to include a greater number of children with PDDs and compensate for the elimination of the home health visitor's observations in the original CHAT.1
The MCHAT (Modified Checklist for Autism in Toddlers) was developed to be a screening tool for autism/PDD at for 18-24 month children in the United States. It could be thought of as a version of the CHAT , which was validated for use in Britain, for the United States medical system. In contrast to the CHAT, which has a section that is filled out by a home health visitor observer,the MCHAT is meant to be completely answered by parents/guardians.1
After an additional followup study into CHAT showed that specific items on the CHAT were key indicators of early signs of autism.2 These questions concerned protodeclarative pointing (pointing at an object of interest), gaze monitoring, and pretend play.
Pediatricians should recommend further evaluation when either two of the six critical items or any of three total items are failed. Scoring criteria are available online at http://www2.gsu.edu/~psydlr/Diana_L._Robins,_Ph.D..html.
Since the MCHAT relies on parent observations, it is possible that parents who are poor observers or judges of their child's behavior may answer questions inaccurately or with much difficulty. Thus, if the clinician has concerns about the child's development. further diagnostic evaluation should be recommended for autism/PDD regardless of scores on the MCHAT.1
Psychometrics (validity and reliability)
Reliability in the initial study introducing the development of the MCHAT was reported using Cronback's alpha for the 22 item checklist and the subset of 6 items which were found to be the best discriminators of children diagnosed with ASD.
Internal reliability for the entire checklist was α=0.85 and α=0.83 for the 6 item subset.
The positive predictive value (PPV), which is the rate at which the children that fail the MCHAT are positively identified as having autism/PDDs through a diagnostic evaluation was PPV=0.058. However, when the followup interview for the MCHAT is conducted in combination with the MCHAT checklist, the PPV=0.57, a moderately high score. Thus, conducting the followup interview is recommended to reduce the number of false positives. While the false positive rate is high, many of the false positives display other types of developmental disabilities and should be treated.3
1.Robins, DL et. al. The Modified Checklist for Autism in Toddlers: an initial study investigating the early detection of autism and pervasive developmental disorders. J Autism Dev Disord. 2001 Apr;31(2):131-44. PMID 11450812
2. Baron-Cohen, S. et. al. Psychological markers in the detection of autism in infancy in a large population. Br J Psychiatry. 1996 Feb;168(2):158-63 PMID 8837904
3. Robins, DL.Screening for autism spectrum disorders in primary care settings.Autism. 2008 Sep;12(5):537-56. PMID 18805946
- Indicators (dependent variables, conditions, or contrasts; measurement variables used for analysis) associated with this task (vote or nominate by editing this page):
Failure of any 2 of 6 critical items or 3 overall.
- Closely related pages (vote or nominate related pages by editing this page):
Other Screening tools
- Primary Species