Development and Psychometric Evaluation of Intention to Drug Avoidance Scale (IDAS) for Thai adolescents

Abstract

The purpose of this study was to develop and evaluate psychometric properties of "Intention to Drugs Avoidance Scale (IDAS)" for Thai Adolescents. This study was divided into two phases: 1) development of the IDAS, and 2) psychometric evaluation. The development of the IDAS process consisted of; 1.1) determination of content domain, this step was composed of the extensive review of literature, concept analysis, and individual interview related to drugs avoidance in adolescents. The preliminary result revealed three components: desire to stay from drugs and to not take drugs, commitment to stay away from drugs and to not take drugs, and willingness to stay away from drugs and to not take drugs, 1.2) item generation, a large item pool was developed for each component, and the total number in the initial item pool was 75 items, and 1.3) the scale format of IDAS was identified using 5 points Likert-like scale, 2) psychometric evaluation consisted of; 2.1) determination of the CVI by 5 experts, some items were revised and deleted, the results showed that the scale consisted of 27 items with the item-level content validity (I-CVI) as 1.00, and scale-level content validity index (S-CVI) as 1.00, 2.2) pre- testing, the 27 items of IDAS was used to perform the pre-testing with 30 adolescents. The whole set of items gained high internal consistency (a = .87), 2.3) field testing consisted of: 2.3.1) exploratory factors analysis, the IDAS was distributed to 369 Thai adolescents from six regions of Thailand, 2.3.2) known group technique, a sample of 60 adolescents (30 for each group). The first group was exposed to drugs and use drugs, and the second group did not use drugs, 2.3.3) test-retest with a sample of 30 students in high school. The results showed the final version of the 22 items of IDAS. Two factors of IDAS were desire and commitment to avoid drugs (15 items), and readiness to avoid drugs (7 items). It accounted for 54.99% of the total variance, and variance of the two factors was 10.73-42.26 with eigenvalue ranged from 2.36-9.74, and factors loading ranged from .54-.86. There was a significantly difference between adolescents who used drugs and not use drugs (z = -6.45, p = <.01). It also showed the Cronbach's alpha coefficient as internal consistency yielded the value of .94, and the alphas of two factors ranged from .86-.93, the stability demonstrated a high-level correlation between time 1 and time 2 (r = .77, p =< .01). The result revealed that the IDAS for Thai adolescents had a valid and reliable property for evaluating the intention to drug avoidance for Thai adolescents. It should be beneficial for researchers and health care providers in using this tool in the future.