Gars-3 Scoring Calculator

The GARS-3 (Gilliam Autism Rating Scale – Third Edition) is a standardized tool used to assess individuals for autism spectrum disorder (ASD). The GARS-3 scoring calculator helps in determining the severity of autism by calculating scores based on specific inputs. This article will explain how the calculator works, its purpose, and provide a step-by-step example.

Purpose and Functionality

The GARS-3 scoring calculator is designed to evaluate various behaviors and developmental milestones across different domains. These domains include:

• Social Interaction: Observing how the individual interacts with others.
• Communication: Assessing both verbal and non-verbal communication skills.
• Emotional Responses: Evaluating emotional reactions and adaptability.
• Cognitive Style: Observing thinking patterns and problem-solving skills.
• Maladaptive Behaviors: Identifying behaviors that are harmful or disruptive.

The age of the person being assessed is also important, as it helps determine the percentile rank and severity level.

Step-by-Step Explanation

1. Inputs: The inputs for the calculator are raw scores from the different subscales mentioned above.
2. Convert Raw Scores to Standard Scores: Each raw score is converted to a standard score using tables from the GARS-3 manual. The formula for conversion is:Standard Score=(Raw Score−MeanStandard Deviation)×Scaling Factor+Mean of Standard Scores\text{Standard Score} = \left( \frac{\text{Raw Score} – \text{Mean}}{\text{Standard Deviation}} \right) \times \text{Scaling Factor} + \text{Mean of Standard Scores}Standard Score=(Standard DeviationRaw Score−Mean​)×Scaling Factor+Mean of Standard ScoresNote: The actual values for the mean, standard deviation, and scaling factor are provided in the GARS-3 manual and differ for each subscale.
3. Calculate Autism Index: The standard scores from each subscale are added together to get the Autism Index.Autism Index=Standard ScoreSocial Interaction+Standard ScoreCommunication+Standard ScoreEmotional Responses+Standard ScoreCognitive Style+Standard ScoreMaladaptive Behaviors\text{Autism Index} = \text{Standard Score}_{\text{Social Interaction}} + \text{Standard Score}_{\text{Communication}} + \text{Standard Score}_{\text{Emotional Responses}} + \text{Standard Score}_{\text{Cognitive Style}} + \text{Standard Score}_{\text{Maladaptive Behaviors}}Autism Index=Standard ScoreSocial Interaction​+Standard ScoreCommunication​+Standard ScoreEmotional Responses​+Standard ScoreCognitive Style​+Standard ScoreMaladaptive Behaviors​
4. Determine Percentile Rank and Severity Level: Using the Autism Index, the percentile rank and severity level are determined based on age norms provided in the GARS-3 manual. The severity level can be categorized as:
   • Very Likely
   • Likely
   • Possible
   • Unlikely

Example Calculation

Let’s consider a 10-year-old child with the following raw scores:

• Social Interaction: 20
• Communication: 15
• Emotional Responses: 18
• Cognitive Style: 22
• Maladaptive Behaviors: 10

Using the GARS-3 manual, we convert these raw scores to standard scores. For illustration purposes, assume the mean is 10 and the standard deviation is 3:

1. Convert Raw Scores to Standard Scores:
   • Social Interaction: Standard Score=(20−103)×10+100=133.33\text{Standard Score} = \left( \frac{20 – 10}{3} \right) \times 10 + 100 = 133.33Standard Score=(320−10​)×10+100=133.33
   • Communication: Standard Score=(15−103)×10+100=116.67\text{Standard Score} = \left( \frac{15 – 10}{3} \right) \times 10 + 100 = 116.67Standard Score=(315−10​)×10+100=116.67
   • Emotional Responses: Standard Score=(18−103)×10+100=126.67\text{Standard Score} = \left( \frac{18 – 10}{3} \right) \times 10 + 100 = 126.67Standard Score=(318−10​)×10+100=126.67
   • Cognitive Style: Standard Score=(22−103)×10+100=140\text{Standard Score} = \left( \frac{22 – 10}{3} \right) \times 10 + 100 = 140Standard Score=(322−10​)×10+100=140
   • Maladaptive Behaviors: Standard Score=(10−103)×10+100=100\text{Standard Score} = \left( \frac{10 – 10}{3} \right) \times 10 + 100 = 100Standard Score=(310−10​)×10+100=100
2. Calculate Autism Index:Autism Index=133.33+116.67+126.67+140+100=616.67\text{Autism Index} = 133.33 + 116.67 + 126.67 + 140 + 100 = 616.67Autism Index=133.33+116.67+126.67+140+100=616.67
3. Determine Percentile Rank and Severity Level:
   • Refer to the GARS-3 manual to find the percentile rank corresponding to an Autism Index of 616.67 for a 10-year-old.
   • Determine the severity level based on the percentile rank.

Relevant Information Table

Conclusion

The GARS-3 scoring calculator is a valuable tool for assessing autism spectrum disorder. By evaluating various behavioral and developmental domains, the calculator helps clinicians and educators to accurately determine the severity of autism. This aids in better diagnosis and planning for interventions, ensuring appropriate support for individuals with autism.