Table 2.
Theoretical concepts, measurement items and item-statistics for the burden scale
| Items | Concepts and Questions | Mean (SD) | Agree / Strongly agree |
IRT p-value# |
|---|---|---|---|---|
| * | Physical and Psychological Burdens | |||
| Burden12 | I would be very disappointed if I received a placebo (an inactive substance) instead of the treatment | 4.04 (1.12) | 75.5% | 0.970 |
| Burden4 | It has made me realize the seriousness of my cancer | 3.23 (1.34) | 50.5% | <.001 |
| Burden6 | I have experienced bothersome side effects | 2.91 (1.32) | 41.3% | <.001 |
| Burden5 | There are unknown side effects that are potentially life threatening | 2.95 (1.04) | 34.3% | <.001 |
| Burden11 | It might not benefit me | 2.69 (1.17) | 31.5% | 0.006 |
| Burden20 | I am uncertain if the research is helping or hurting me | 2.64 (1.11) | 24.5% | <.001 |
| Burden16 | I have to rely on others for my needs (financial, personal care, support) | 2.29 (1.20) | 21.8% | <.001 |
| Burden2 | It has added stress to managing my cancer (for example, trying to coordinate services for my care in seeing different doctors, bills, paperwork, traveling with X-rays and MRIs etc.) | 2.38 (1.11) | 19.3% | <.001 |
| Burden22 | I am tired because of my research participation | 18.2% | <.001 | |
| Burden7 | My quality of life is less | 2.33 (1.08) | 16.7% | <.001 |
| Burden10 | I am not learning anything more about my cancer from being in a research study | 2.29 (1.05) | 12.0% | <.001 |
| Burden14 | The amount of information that I needed to understand (to be in the study) is overwhelming | 2.18 (0.93) | 10.9% | <.001 |
| Burden21 | I often wonder if the researcher is not telling me everything about my treatment | 2.05 (0.96) | 10.0% | <.001 |
| Burden15 | I worry that I did not understand everything about the research and what it meant when I agreed to be in the study | 2.06 (0.90) | 9.1% | <.001 |
| Burden19 | I sometimes feel like a guinea pig | 1.81 (0.91) | 7.3% | <.001 |
| Burden18 | Others perceive me as a guinea pig | 1.82 (0.90) | 4.5% | <.001 |
| Social and Economic Burdens | ||||
| Burden13 | It makes me worry about other family members who could be at risk for cancer | 3.12 (1.19) | 41.8% | <.001 |
| Burden3 | I have had to rearrange my life in order to take part in research (for example, travel time, being out of work, meeting scheduled appointments) | 2.78 (1.32) | 38.5% | <.001 |
| Burden23 | It is costing me money out of pocket | 2.45 (1.22) | 25.2% | <.001 |
| Burden17 | My insurance does not cover all the costs of being in the study | 2.47 (1.22) | 23.1% | <.001 |
| Burden1 | I have additional personal responsibilities that I did not expect | 2.33 (1.05) | 14.7% | <.001 |
| Burden8 | I find it difficult to balance my family needs with my own needs for treatment | 2.04 (1.02) | 12.0% | <.001 |
| Burden9 | I worry that it is difficult for my family (including children) to see me take part in a research study for my cancer | 1.96 (1.04) | 11.0% | <.001 |
| Total | Scale Mean Score | 2.48 (0.58), 1.00–3.82 | ||
*
The number is the sequential order of the item in the actual scale.
#
p-value from IRT graded response model discrimination.
Items were measured on a Likert scale from 1 (Strongly Disagree) to 5 (Strongly Agree)
Alpha=0.873 for the total scale (number of items=23)
The distribution of burden mean scale score is normal (skewness=−0.17, SE=0.23, kurtosis=−0.05, SE=0.46)