How to compute a self-creating scale’s validity?

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Computing the validity of a self-created scale involves assessing whether the scale accurately measures the construct it intends to measure. Here are some steps to compute the validity of a self-creating scale:
1. Conceptual clarity: Ensure that the construct you are measuring is well-defined and conceptually clear. Review relevant literature and theories to establish a solid conceptual foundation for your construct. Clearly articulate the construct's definition and the specific aspects or dimensions you aim to capture.
2. Item generation: Generate a pool of items that represent the construct you want to measure. These items should reflect different aspects or dimensions of the construct and be relevant to the target population. Consider using existing validated scales or adapting items from previous studies as a starting point. Aim for a sufficient number of items to capture the construct comprehensively.
3. Content validity: Evaluate the content validity of the scale by assessing whether the items adequately represent the construct being measured. Subject matter experts, such as researchers or professionals familiar with the construct, can review the items and provide feedback on their relevance and representativeness. Consider their suggestions to refine the item pool and ensure content validity.
4. Pilot testing: Conduct a pilot study with a small sample of participants from the target population. Administer the scale to the participants and collect their responses. Analyze the data to assess item characteristics, such as item-total correlations, to identify problematic items that may need revision or removal. Pilot testing helps refine the scale and improve its psychometric properties.
5. Construct validity: Establish the construct validity of the scale by examining its relationship with other variables or constructs. This can be done through statistical analysis, such as correlation analysis or factor analysis. Assess whether the scale demonstrates convergent validity (strong correlations with similar constructs) and discriminant validity (weak correlations with unrelated constructs).
6. Criterion validity: If appropriate, assess the criterion validity of the scale by comparing the scores on your self-created scale with an established and validated measure of the same construct. This can be done by administering both scales to the same participants and examining the correlation between the scores. A strong correlation indicates good criterion validity.