Designing and Assessing the Validity and Reliability of the Bayley-III Test Examiner Clinical Performance Scale

In recent years, the infant development and assessment programs have received attention by the health system of Iran. In this regard, the training of examiners for performing the Bayley tests has become one of the needs of the health system. This study aims to design and evaluate the validity and reliability of the Bayley-III examiner clinical performance scale.

this study, participants were Bayley-III test examiners from medical universities in Iran, who were selected using a purposive sampling method. First, in focused group discussion sessions with 10 Bayley-III test experts, the items of instrument were formulated. Then, to evaluate the face validity, the questionnaire was sent to a panel of expert consisting of 8 Bayley-III experts and examiners and they were asked to rate the items from 1 to 5 in terms of importance. The items with an impact score of less than 1.5 were deleted, and other items were revised, if needed. To evaluate content validity, the questionnaire was sent to 10 Bayley-III test experts, and then the content validity ratio (CVR) and content validity index (CVI) were measured. The items with CVR <0.6 and CVI <0.7 were deleted. The reliability of the instrument was assessed by calculating the inter-rater reliability, test re-test reliability, and internal consistency. Quantitative data analysis was done in SPSS software, version 22.

The instrument with 66 items, including 32 items for the cognitive domain, 22 items for the language domain (13 for receptive and 9 for expressive components), 12 items for the motor domain (9 for fine and 3 for gross motor skills), and 14 items for the general section, was assessed in stability and reliability. The intraclass correlation coefficient (ICC) for the test re-test reliability was obtained 0.83 for the specific section and 0.86 for the general section. The ICC for the inter-rater reliability was 0.80 (95% CI: 58-82). The highest correlation value was related to the cognitive scale (0.88), and the lowest value was for the gross motor skill subscale (0.76). The kappa coefficient for the inter-rater reliability of the general section was above 0.7. The kappa coefficient for the specific section ranged from 1 to 0.35. The Cronbach’s α for the internal consistency of the general section was 0.76. 

The designed questionnaire is a valid and reliable tool to evaluate the clinical performance of Bayley-III test examiners in Iran.