| Instrument | Description | Reliability | Validity |
| The Purpose in Life Test (PIL) ( | 20-item self-report attitude questionnaire that makes reference to both meaning and purpose. All items follow a structure pattern of a 7-point scale from 1 (low purpose) to 7 (high purpose). | Coefficient alphas from .86 to .88 ( | Correlates inversely with suicidal ideation ( |
| The Purpose in Life Test-Short Form (PIL-SF) ( | 4 items extracted from the 20 items of the PIL. | Coefficient alphas in the .80s ( | Correlates with measures of well-being and psychological distress ( |
| The Meaning in Life Questionnaire (MLQ) ( | 10-item self-report questionnaire that measures life meaning and search for meaning. All items follow a structure pattern of a 7-point Likert scale that ranges from 1 (absolutely untrue) to 7 (absolutely true). | Coefficient alphas ranging from .08 to .09 ( | Significant correlation between the MLQ and the PIL ( |
| The Authenticity Inventory (AI) ( | 45-item self-report questionnaire that uses a four-factor construction of authenticity: (1) Awareness (A); (2) Unbiased processing (UP); (3) Behavior (B); and (4) Relational orientation (RO). Respondents rate their degree of agreement on a 5-point scale that ranges from 1 (strongly disagree) to 5 (strongly agree) for all items. | Alpha coefficients: Factor 1 (A): .79 Factor 2 (UP): .64 Factor 3 (AL): .80 Factor 4 (RO): .78 ( | Correlates with psychological well-being measures. ( |
| The Authenticity Scale (AS) ( | 12-item self-report questionnaire that uses a three-factor construction of authenticity: (1) Self-alienation (SA); (2) Authentic living (AL); and (3) Accepting external influences (AEI). All items use a 7-point self-description scale that ranges from 1 (does not describe me at all) to 7 (describes me very well). | Alpha coefficients: Factor 1 (AL): .70 to .82 Factor 2 (SA): .82 to .84 Factor 3 (AEI): .77 to .84 ( | Correlated with self-esteem, subjective well-being, and psychological well-being ( |