Part 1:
1.Choose a paper describing the development or validation of a measure of relevance in health disparities research (please give the full citation and/or upload the paper if that's possible).
Wang, C. T., Greenwood, N., White, L. F. and Wilkinson, J. (2015), Measuring Preparedness for Mammography in Women with Intellectual Disabilities: A Validation Study of the Mammography Preparedness Measure. J Appl Res Intellect Disabil, 28: 212–222. doi:10.1111/jar.12123s
2.What was the definition of the construct?
The Mammography Preparedness Measure (MPM) is a measure of the respondent’s desire to be prepared for a mammography, specifically designed for women with intellectual disabilities. It is distinct from the standardized instrument used for the general population, the Breast Cancer and Heredity Knowledge Scale (BCHK) in that it uses concrete wording and collects information directly from the women themselves, rather than a caregiver, in an effort to better gauge level of understanding of the respondent.
3.How did the authors provide evidence on the validity of the measure? Could you think of additional approaches to validating the measure?
The authors first evaluated the BCHK, designed to measure breast cancer and mammography knowledge in the general population, by administering it to a sample of women with intellectual disabilities and analyzing the content of their responses. Content analysis indicated that respondents often did not understand the BCHK questions and had a 50% chance of guessing answers, which are in true/false format, correctly. After developing the new measure, the MPM, the authors tested its validity by pilot testing and performing cognitive interviews with women with intellectual disabilities to assess face and content validity (whether the questions reflect their true meaning and are clear, respectively). They also sought opinions from staff regarding the validity of the MPM test for mammogram preparedness. The authors used the respondents’ comments during this testing to assess validity.
This study is motivated by the disparity between women with and without intellectual disabilities, as the former receive regular mammography less frequently and have higher incidences of cancer mortality rates. It proposes the MPM as a preferred instrument for women with intellectual disabilities, but does not quantitatively compare it to the standard measure or absence of the new measure and its intended results – to increase the rate of regular mammography. Since validity “refers to the degree to which results of a measurement correspond to the actual outcome,” a measurement of whether or not the MPM results in higher rates of mammography among women with intellectual disabilities is a good first step.(Hidalgo and Goodman) With access to clinical records this would be straightforward to collect.
Hidalgo B, Goodman M. Validation of Self-Reported Measures in Health Disparities Research. Journal of biometrics & biostatistics. 2012;3(7):1000e114. doi:10.4172/2155-6180.1000e114.
4.How did the authors provide evidence on the reliability of the measure? Could you think of additional approaches to evaluating the reliability of the measure?
The authors assessed test-retest reliability by an absolute difference in percent agreement between the first and second tests administered and calculating the overall kappa. They believed that if answers remain stable over time, it demonstrates respondent understanding (as the major issue with the previously used instrument was that there may have been high rates of random guessing).
To improve the reliability of this measure, the authors could have translated the MPM into additional languages, as it would likely be more meaningful for many participants in a language other than English. Also, alternative psychometric approaches besides test-retest could have been used, such as internal consistency.
5.Describe the implications of a lack of measurement validity or reliability for future research applications.
The most pressing implication of a lack of measurement validity or reliability for future research applications is that the measure will not achieve its intended outcomes – higher rates of mammography among women with intellectual disabilities. Even worse, respondents could be further confused by the MPM, causing them to think that regular mammography are unimportant, not to be performed regularly, or to be feared, further widening the disparity. For example, by assessing reliability just with test-retest, participants could answer the second test by recalling their answers from the first test, rather than by demonstrating cognition and understanding. More than one reliability test should be used.
Part 2:
1.Find a paper describing a health disparity (please give the full citation or upload the paper)
Boscoe FP, Johnson CJ, Sherman RL, Stinchcomb DG, Lin G, Henry KA. The Relationship Between Area Poverty Rate and Site-Specific Cancer Incidence in the United States. Cancer. 2014;120(14):2191-2198. doi:10.1002/cncr.28632.
2.Summarize the construct and measurement of the dimension of disparity (e.g., race, SES) and the outcome measured (e.g., self-rated health).
The authors examine the relationship between area poverty rate by census tract and the incidence of site-specific cancer in the United States. SES reporting within cancer surveillance is rare because SES is not often collected in public health data systems. Using residential address and county level data are problematic due to issues of privacy and heterogeneity, respectively. The authors report on SES by census-tract poverty rate because, at this level, there are fewer sensitivity and heterogeneity issues. It should be recognized, while census tracts may serve as a rough estimate for household poverty rate, they are by no means a representation of a homogenous group of households.
Across all cancer sites, the authors did not find a significant association between cancer rates and poverty. However, individual cancer sites showed positive and negative associations with poverty. Additionally, cancer sites associated with higher rates of poverty exhibited lower incidence and higher mortality compared to cancer sites associated with lower rates of poverty.
3.What is the evidence for the validity and reliability of the measures?
The authors deemed an examination of the relationship between SES and cancer rates valid due to a plethora of evidence demonstrating that most diseases and poor health conditions show a SES gradient. Existing literature discusses the incidences of certain types of cancer in individuals with low SES.
There is no evidence for reliability testing of this measure. Steps towards reliability would include efforts to add dynamic SES data to population health management tools.
4.What is the reference category used for the disparity measure? Why does this reference category make sense (or not) for this research question?
The reference categories for risk ratios of cancer incidence are the highest and lowest poverty categories. This makes sense because it highlights the cancer sites with the most extreme mortality rates (and the cancers that should perhaps be targeted first).
5.How is the disparity quantified? Is this an absolute or relative measure or are both provided? Describe which type of measure you would prefer for this research area, or, if both, why.
The risk ratio of cancer incidence by SES is quantified by rate of diagnosis of 39 different types of site-specific cancer by poverty category ((<5%, 5%<10%, 10%<20%, >=20% individuals living below the poverty line in census tract). They use an absolute measure by examining the difference in risk of various types of cancer between the greatest and lowest poverty categories. This is the preferred measure for this specific set of data as the authors are comparing different types of cancer, rather than a single type of cancer’s rate of incidence over time. A relative comparison would not be appropriate with the data in hand as it would ask for a comparison between two different types of cancer with two very different inherent levels of risk.