Self-Care Scoring Algorithm
This scoring algorithm can be used to calculate responses to the all of the documents found on this site.
All of the scales are scored in the same fashion, although we provide SPSS syntax only for the SCHFI below. Do not compute a total score. Instead, calculate separate scores for each scale separately. Confidence is not part of self-care per se, but an important process that mediates or moderates the relationship between self-care and outcomes. Computing scores in this fashion will allow you to obtain self-care scores even in asymptomatic patients because the self-care management scales are computed only when patients have been symptomatic.
In general, to standardize a scale score, 1) determine the maximum possible scale score, 2) subtract the number of items from the possible score, and 3) divide 100 by that result to identify a constant for that scale. To score the scale, sum item responses, subtract the number of items answered, and multiply by the constant.
For the SCHFI, specific formulas for calculating scale scores are available in the 2009 article. The examples below address the SCHFI.
Maintenance. To calculate the Maintenance scale scores, each scale score is standardized to a 0 to 100 range. If you are using a version with a negatively worded item, reverse-code that item and then standardize the raw score to a 0-100 scale. Note that more than half of the items in this section A should be answered for the scale to be an adequate measure of self-care maintenance.
Management. Score the management scale only if the patient reported having trouble breathing or ankle swelling. Otherwise, ignore responses, even if the patient answers the items. Note that the first item (In the past month, have you had trouble breathing or ankle swelling?) is used only to identify symptomatic patients, not in the scale score. At least 2 of the 4 possible remedies must be answered for the scale to be an adequate measure of self-care management.
Confidence. Self-care confidence scores (Section C) should be standardized as described above. Note that more than half of the items in this section should be answered for the scale to be an adequate measure of self-care confidence.
SPSS Syntax for Scoring the SCHFI:
Here is some useful SPSS syntax for the SCHFIv6.2 (22 items). We are using different names and labels for these items. I just wrote the item numbers so that you can search and replace these with your own labels (e.g. first question = SCHFI1).
Please make sure that missing values (often written as 9, -9, or 99) are correctly specified in SPSS. Otherwise, you will be likely to have some high (>100) or low (<0) scores. Also, scores for subjects with missing data have to be calculated separately, depending on how many and which items they missed.
First, recode any negatively worded item:
RECODE SCHFI8 (1=4) (2=3) (3=2) (4=1).
Second, compute the Self-Care Maintenance score:
Third, select patients who responded “yes”/1 to the first question under section B, and compute the Management score; be sure to replace “BreathAnkl” with your variable name.
IF (BreathAnkl=1) SCHFIManagement=(SUM(SCHFI11,SCHFI12,SCHFI13,SCHFI14,SCHFI15, SCHFI16)-4)*5.
Fourth, compute the Confidence score.