Multidimensional Fatigue Inventory (MFI-20)

The MFI-20 treats fatigue as five separate things rather than one. Someone whose legs feel heavy is experiencing something different from someone who cannot concentrate, and different again from someone who has simply stopped doing much — and a single severity rating would flatten all three into the same number.

Twenty statements describe how a person has been feeling lately. Four belong to each of five dimensions: general fatigue, physical fatigue, mental fatigue, reduced activity, and reduced motivation. Each is rated on a five-point scale from "yes, that is true" to "no, that is not true". Half the statements are worded positively and are reverse-scored. Each subscale totals 4 to 20, with higher meaning more fatigue.

• Further validation of the Multidimensional Fatigue Inventory in a US adult population sample

Licensing Notes: MFI-20 is a registered trademark

Learn More: The developers do not recommend using a total score across all 20 items. The five dimensions were designed to be read separately.

Commonly cited clinical cut-points are 11 for general fatigue, 10 for reduced activity, and 9 for physical fatigue, mental fatigue, and reduced motivation.