Computing Raw Scale Scores

After item cleaning, including handling of missing data (see below), a raw score is computed for each scale. This score is the simple algebraic sum of responses for all items in that scale. For example, the raw scale score for the Self-Care Maintenance Scale is the sum of the responses to items in section A.

Missing data

You can use imputed values or change the denominator in the transformation formula (see below) to accommodate missing items. We recommend that if the respondent answers ≥50% of the items in a multi-item scale (e.g., Self-Care Maintenance), the score should be calculated. If the respondent answered <50% of the items, the score for that scale should be considered missing.

This simple scoring method is possible because items in the same scale have roughly equivalent relationships to the underlying concept being measured and no item is used in more than one scale. Thus, it is not necessary to weight items. These are the assumptions used in calculating the commonly used SF-36.

Transformation of Scale Scores

The next step involves transforming each raw scale score to a 0 – 100 scale using the formula shown below. The Table below shows an example of this process. The Table provides the information necessary to apply this formula to each scale in the Self-Care of Chronic Illness Inventory (SC-CII) as an example. Use the same principle when computing scores for the other scales.

This transformation converts the lowest and highest possible scores to 0 and 100, respectively. Scores between these values represent the percentage of the total possible score achieved.

Scale

Sum final item values

Lowest and highest possible raw scores

Possible raw score range

Self-Care Maintenance

(Section A)

1+2+3+4+5+6+7

7, 35

28

Self-Care Monitoring 

(Section B)

8+9+10+11+12*

5, 25

20

Self-Care Management

(Section C)

14+15+16+17+18

5, 25

20