High-quality, real-scale studies require validated instruments to ensure reliability and relevance. Content validity is a critical prerequisite in instrument development, reflecting the degree to which the items accurately represent the intended concepts. This study aimed to develop a smoking behavior instrument grounded in the Theory of Planned Behavior (TPB) and evaluate its content validity through expert assessment. The study was conducted in two stages. The first stage involved designing the instrument through a comprehensive literature review on smoking behavior and constructing items aligned with the TPB framework. The second stage assessed the instrument's content validity using the Content Validity Index (CVI) methodology, with input from four expert panelists.
40 items were developed: 12 for the attitude variable, 11 for subjective norms, 11 for behavioral control, and 6 for intention. The CVI scores ranged from 0.75 to 1.0 across all items, indicating high content validity. The smoking behavior instrument based on the TPB indicating high content validity for future stidies. This validated instrument provides a reliable tool for studying smoking behavior within the TPB framework. Further psychometric testing, including construct validity and reliability analysis, is recommended for broader applicability. Furthermore, this instrument has very high potential to be applied in public health, especially in efforts to stop smoking.

High-quality, real-scale studies require validated instruments to ensure reliability and relevance. Content validity is a critical prerequisite in instrument development, reflecting the degree to which the items accurately represent the intended concepts. This study aimed to develop a smoking behavior instrument grounded in the Theory of Planned Behavior (TPB) and evaluate its content validity through expert assessment. The study was conducted in two stages. The first stage involved designing the instrument through a comprehensive literature review on smoking behavior and constructing items aligned with the TPB framework. The second stage assessed the instrument's content validity using the Content Validity Index (CVI) methodology, with input from four expert panelists.
40 items were developed: 12 for the attitude variable, 11 for subjective norms, 11 for behavioral control, and 6 for intention. The CVI scores ranged from 0.75 to 1.0 across all items, indicating high content validity. The smoking behavior instrument based on the TPB indicating high content validity for future stidies. This validated instrument provides a reliable tool for studying smoking behavior within the TPB framework. Further psychometric testing, including construct validity and reliability analysis, is recommended for broader applicability. Furthermore, this instrument has very high potential to be applied in public health, especially in efforts to stop smoking.