Midlife Development Inventory Personality Trait Scales – MIDI Personality Scales
A self-report instrument designed to assess the Big Five personality traits and Agency in adulthood.
Scale Development & Technical Details
Scale Overview
The Midlife Development Inventory Personality Trait Scales – MIDI Personality Scales was developed by Margie E. Lachman, S. L. Weaver (1997). It is designed to measure Personality Traits. The scale is intended for use with Adults.
Scale Structure
This instrument consists of 31 items organized into 6 factors/subscales: Neuroticism, Extraversion, Openness to Experience, Conscientiousness, Agreeableness, Agency.
| Factor / Subscale | Items | N |
|---|---|---|
| Neuroticism | 3,8,13,19 | 4 |
| Extraversion | 1,6,11,23,27 | 5 |
| Openness to Experience | 14,17,21,22,25,28,29 | 7 |
| Conscientiousness | 4,9,16,24,31 | 5 |
| Agreeableness | 2,7,12,18,26 | 5 |
| Agency | 5,10,15,20,30 | 5 |
Response Format
Respondents rate each item using a custom response format.
Response anchors: 1 = A lot, 2 = Some, 3 = A little, 4 = Not at all.
The scale includes 2 reverse-scored items to reduce acquiescence bias.
Scoring
Items are scored by subscale, with each subscale sum representing a distinct dimension.
Psychometric Properties
Internal Consistency: The scale has demonstrated good to excellent internal consistency with reported Cronbach’s alpha values of Neuroticism: 0.74, Extraversion: 0.78, Openness to Experience: 0.77, Conscientiousness: 0.58, Agreeableness: 0.80, Agency: 0.79.
Administration
The scale is self-administered and typically takes approximately 5 minutes to complete. It can be administered individually or in group settings. No special training is required for administration.