Midlife Development Inventory Personality Scales – MIDI Personality Scales
A self-report assessment of the Big Five personality traits and Agency designed for midlife and adult development research.
Scale Development & Technical Details
Scale Overview
The Midlife Development Inventory Personality Scales – MIDI Personality Scales was developed by Margie E. Lachman, Sharon L. Weaver (1997). It is designed to measure Personality (Big Five and Agency). 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.
Total scores range from 1 to 4. Interpretation guidelines:
- Low description / Low expression of trait: 1 – 2
- Moderate description / Moderate expression of trait: 2 – 3
- High description / High expression of trait: 3 – 4
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.