Original article
Validity of the revised Impact on Family (IOF) scale

https://doi.org/10.1016/j.jpeds.2006.04.003Get rights and content

Objective

To assess psychometric properties of the revised 15-item Impact on Family (IOF) Scale.

Study design

A secondary analysis of items using data collected from 252 parents during an earlier randomized clinical trial.

Results

Exploratory factor analysis and confirmatory factor analysis identified a single factor with factor loadings similar to that of IOF developers. The one factor accounts for 45.7% of the sample variance. An Item Response Theory analysis found that 11 of the 15 items had α values greater than 1.00, with good to excellent item characteristic and item information curves. The test information and measurement error curves for the entire IOF were excellent. Construct validity of the IOF also was supported. Parent IOF scores correlated in the expected directions with maternal mood (r = −0.50), sibling behavior problems (r = −0.35), and severity of illness (r = 0.31) and were associated with family socioeconomic status (t = −4.5, all P < .001).

Conclusions

This study provides independent support for validity and reliability of the revised IOF scale. This scale is a promising, easy-to-use instrument for the measurement of impact of illness and disability on families of children with chronic illness or disability.

Section snippets

Methods

In 1998 to 2002, during the ISEE study, which was reported in this Journal, Williams et al5 collected baseline data from parents (1998 to 1999), using the 24-item Stein-Riessman IOF scale. These IOF results, however, were not further used or reported, since the 24-item scale failed to produce a scalable construct. A number of items cross-loaded on multiple factors and patterns of intercorrelation were inconsistent. All IOF data were retained after conclusion of the ISEE. Retention of these data

Study Question 1: EFA and CFA

The EFA produced two factors, but the second factor was a poor construct. The first factor had an eigenvalue of 6.8502 and accounted for 45.7% of the variance in the sample. The second factor eigenvalue, however, was barely greater than 1 (1.0473) and accounted for less than 7% to the variance in the sample. In total, the two factors accounted for 52.7% of the variance in the sample.

The varimax rotated factor loadings of the two factors, moreover, were difficult to interpret. Although the

Discussion

Our results generally support the findings of Stein and Jessop4 that the 15 items on their scale measure a single construct. The marginal values of the NFI and RMSEA are of some concern; yet, the model fit appears satisfactory. This is particularly so because the revised IOF is well supported in the IRT analysis and appears to have good construct validity. Additional studies of the revised Impact of Family Scale, however, might lead to further improvements in the instrument. A few items

References (29)

  • Scientific Software International. MultiLog 7.03

    (2003)
  • F.B. Baker

    The Basics of Item Response Theory

    (2001)
  • S.E. Embretson et al.

    Item response theory for psychologists

    (2000)
  • D. McNair et al.

    POMS ManualProfile of Mood States

    (1992)
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    The ISEE study was funded in 1998 to 2002 through a grant (RO1 NR947110) awarded to the PI (Phoebe D. Williams, PhD) by the National Institutes of Health, National Institute of Nursing Research, Bethesda, Maryland.

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