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1.  Initial validation of a self-report measure of the extent of and reasons for medication nonadherence 
Medical care  2012;50(12):1013-1019.
Self-report measures of medication nonadherence confound the extent of and reasons for medication nonadherence. Each construct is assessed with a different type of psychometric model, which dictates how to establish reliability and validity.
To evaluate the psychometric properties of a self-report measure of medication nonadherence that assesses separately the extent of nonadherence and reasons for nonadherence.
Research Design
Cross sectional survey involving the new measure and comparison measures to establish convergent, discriminant, and concurrent validity. The new measure was re-administered 2 to 21 days later.
202 veterans with treated hypertension were recruited from the Durham Veterans Affairs Medical Center.
A new self-report measure assessed the extent of nonadherence and reasons for nonadherence. Comparison measures included self-reported medication self-efficacy, beliefs about medications, impression management, conscientiousness, habit strength, and an existing nonadherence measure.
Three items assessing the extent of nonadherence produced reliable scores for this sample, alpha=0.84 (95% CI: 0.80, 0.87). Correlations with comparison measures provided evidence of convergent and discriminant validity. Correlations with systolic (r=0.27, p<.0001) and diastolic (r=0.27, p<.0001) blood pressure provided evidence of concurrent validity. Reasons for nonadherence was assessed with 21 independent items. Intraclass correlations (ICC) were 0.58 for the extent score and ranged from 0.07 to 0.64 for the reasons.
The dual conceptualization of medication nonadherence allowed a stronger evaluation of the reliability and validity than was previously possible with measures that confounded these two constructs. Measurement of self-reported nonadherence consistent with psychometric principles will enable reliable, valid evaluation of interventions to reduce nonadherence.
PMCID: PMC3494794  PMID: 22922431
adherence; reliability; scale development; self-report
2.  Characterizing weekly self-reported antihypertensive medication nonadherence across repeated occasions 
Little is known about weekly variability in medication nonadherence both between and within persons.
To characterize medication nonadherence across repeated, closely spaced occasions.
This prospective cohort study comprised four unannounced telephone assessment occasions, each separated by approximately 2 weeks. On each occasion, adult outpatients taking at least a single antihypertensive medication completed a measure of extent of, and reasons for, nonadherence.
Two hundred and sixty-one participants completed 871 (83%) of 1,044 occasions. Nonadherence was reported on 152 (17.5%) of 871 occasions by 93 (36%) of 261 participants. The most commonly endorsed reasons for nonadherence were forgetting (39.5%), being busy (23.7%), and traveling (19.7%). Among 219 participants completing at least three occasions, 50% of the variability in extent of nonadherence was a result of within-person fluctuations, and 50% was a result of between-person differences.
Interventions to reduce nonadherence should be informed by variability in the extent of nonadherence and specific reasons for nonadherence.
PMCID: PMC4019621  PMID: 24855340
adherence; compliance; hypertension; intraindividual variability
3.  Informing the Dosing of Interventions in Randomized Trials 
Contemporary clinical trials  2012;33(6):1225-1230.
Dosing is potentially the most important decision that must be made when building or refining behavioral interventions. In this paper, we propose standardized terminology and reporting of dosing information, which would inform intervention development, refinement for dissemination, and systematic reviews of dose-response relationships. Dosing of interventions may be characterized by duration, frequency, and amount. To illustrate the value of operationalizing these three parameters to evaluate dose-response relationships, 31 published reports of behavioral interventions to increase adherence to antiretroviral therapy (ART) were reviewed. The ART literature was characterized by under-reporting of dosing parameters, heterogeneity in dosing schedules, and heterogeneity in type of control group, which complicate analysis of dose-response relationships in systematic review and determination of the optimal dose for intervention dissemination. Improved reporting of the three dosing parameters and comparison of intended to actual delivery can inform the identification of the most effective intervention doses and the efficient implementation of efficacious interventions in clinical practice.
PMCID: PMC3468665  PMID: 22841930
clinical trial; randomized controlled trial; study characteristics; intervention studies; patient adherence; intervention dose
4.  Combining adjusted and unadjusted findings in mixed research synthesis 
Rationale, aims and objectives
Finding ways to incorporate disparate types of evidence into research syntheses has the potential to build a better evidence base for clinical practice and policy. Yet conducting such mixed research synthesis studies is challenging. Researchers have to determine whether and how to use adjusted and unadjusted quantitative findings in combination with each other and with qualitative findings.
Among quantitative findings, adjustment for confounding, either via study design or statistical analysis, can be a considerable source of heterogeneity. Yet there is no consensus about the best way to synthesize findings resulting from different methods for addressing confounding. When synthesizing qualitative and quantitative findings, additional considerations include determining whether findings are amenable to synthesis by aggregation or configuration, which, in turn, depends on the degree of interpretive transformation of findings.
Qualitative survey findings appear similar in form to unadjusted or minimally adjusted quantitative findings and, when addressing the same relationship, can be summed. More interpreted qualitative findings appear similar in form to adjusted findings found in, for example, structural equation models specifying the relationship among a host of latent variables. An option for synthesis of conceptually similar models is reciprocal translation.
These decisions will ultimately be judged on the meaningfulness of their results to practice or policy.
PMCID: PMC3063329  PMID: 21040243
adjustment; confounding; meta-analysis; qualitative research; quantitative research; research synthesis
5.  Patient perspectives on having multiple versus single prescribers of chronic disease medications: results of a qualitative study in a veteran population 
Patients with multiple chronic conditions often have multiple prescribers, which has been associated with greater health care utilization and medication nonadherence in claims-based analyses. This qualitative study was conducted to understand the reasons why patients have increasing numbers of prescribers of medications and to understand patient perspectives on advantages and disadvantages of having multiple prescribers, including effects on medication supply.
This qualitative study involved three focus groups comprising 23 outpatients from a single Veterans Affairs (VA) Medical Center with at least one chronic cardiometabolic condition (hypertension, diabetes, dyslipidemia, or congestive heart failure). Participants were asked about their experiences, including perceived of advantages and disadvantages, of having multiple prescribers of cardiometabolic medications. Conventional content analysis was used to analyze the data.
Multiple prescribers arose through referrals and patients actively seeking non-VA prescribers (primary care and/or specialist) to maximize timeliness and access to medications, provide access to medications not on the VA formulary, and minimize out-of-pocket costs. Patients seeking non-VA care had to coordinate own their care by sharing prescriptions and test results to their prescribers within and outside VA.
Prescribing physicians should engage in open dialogue with patients to create a shared understanding of patient and provider goals and priorities for chronic disease medications.
PMCID: PMC4233094  PMID: 25344128
Comorbidity; Multi-morbidity; Complex patient; Prescriber; Provider; Veterans
6.  Selective adherence to antihypertensive medications as a patient-driven means to preserving sexual potency 
To describe hypertensive patients’ experiences with sexual side effects and their consequences for antihypertensive medication adherence.
Data were from a study conducted to identify facilitators of and barriers to adherence to blood pressure-lowering regimens. Participants were 38 married and unmarried veterans with a diagnosis of hypertension and 13 female spouses. Eight patient and four spouse focus groups were conducted. A directed approach to content analysis was used to determine the facilitators of and barriers to adherence. For this report, all discussion concerning the topic of sexual relations was extracted.
Male patients viewed sexual intercourse as a high priority and felt that a lack of sexual intercourse was unnatural. They pursued strategies to preserve their potency, including discontinuing or selectively adhering to their medications and obtaining treatments for impotence. In contrast, spouses felt that sexual intercourse was a low priority and that a lack of sexual intercourse was natural. They discouraged their husbands from seeking treatments for impotence.
Although the primary study was not designed to explore issues of sexual function, the issue emerged spontaneously in the majority of discussions, indicating that sexuality is important in this context for both male patients and their spouses. Physicians should address sexual side effects of antihypertensive medications with patients, ideally involving spouses.
PMCID: PMC2770379  PMID: 19920964
hypertension; sexual side effects; antihypertensive medication; adherence; blood pressure
7.  Recruiting young adults into a weight loss trial: Report of protocol development and recruitment results 
Obesity has spread to all segments of the U.S. population. Young adults, aged 18-35, are rarely represented in clinical weight loss trials. We conducted a qualitative study to identify factors that may facilitate recruitment of young adults into a weight loss intervention trial. Participants were 33 adults aged 18-35 yrs with BMI > 25 kg/m2. Six group discussions were conducted using the nominal group technique. Health, social image, and “self”factors such as emotions, self-esteem, and confidence were reported as reasons to pursue weight loss. Physical activity, dietary intake, social support, medical intervention, and taking control (e.g. being motivated) were perceived as the best weight loss strategies. Incentives, positive outcomes, education, convenience, and social support were endorsed as reasons young adults would consider participating in a weight loss study. Incentives, advertisement, emphasizing benefits, and convenience were endorsed as ways to recruit young adults. These results informed the Cellphone Intervention for You (CITY) marketing and advertising, including message framing and advertising avenues. Implications for recruitment methods are discussed.
PMCID: PMC3765064  PMID: 23591327
Obesity; young; adults; recruitment; methods; trial
9.  Physician Perceptions on Colonoscopy Quality: Results of a National Survey of Gastroenterologists 
Background. Quality indicators for colonoscopy have been developed, but the uptake of these metrics into practice is uncertain. Our aims were to assess physician perceptions regarding colonoscopy quality measurement and to quantify the perceived impact of quality measurement on clinical practice. Methods. We conducted in-person interviews with 15 gastroenterologists about their perceptions regarding colonoscopy quality. Results from these interviews informed the development of a 34-question web-based survey that was emailed to 1,500 randomlyselected members of the American College of Gastroenterology. Results. 160 invitations were undeliverable, and 167 out of 1340 invited physicians (12.5%) participated in the survey. Respondents and nonrespondents did not differ in age, sex, practice setting, or years since training. 38.8% of respondents receive feedback on their colonoscopy quality. The majority of respondents agreed with the use of completion rate (90%) and adenoma detection rate (83%) as quality indicators but there was less enthusiasm for withdrawal time (61%). 24% of respondents reported usually or always removing diminutive polyps solely to increase their adenoma detection rate, and 20% reported prolonging their procedure time to meet withdrawal time standards. Conclusions. A minority of respondents receives feedback on the quality of their colonoscopy. Interventions to increase continuous quality improvement in colonoscopy screening are needed.
PMCID: PMC3963379  PMID: 24734039
11.  Community-based HCV screening: knowledge and attitudes in a high risk urban population 
In an attempt to curtail the rising morbidity and mortality from undiagnosed HCV (hepatitis C virus) in the United States, screening guidelines have been expanded to high-risk individuals and persons born 1945–1965. Community-based screening may be one strategy in which to reach such persons; however, the acceptance of HCV testing, when many high-risk individuals may not have access to HCV specific medications, remains unknown.
We set out to assess attitudes about HCV screening and knowledge about HCV disease at several community-based testing sites that serve high-risk populations. This assessment was paired with a brief HCV educational intervention, followed by post-education evaluation.
Participants (n = 140) were surveyed at five sites; two homeless shelters, two drug rehabilitation centers, and a women’s "drop-in" center. Personal acceptance of HCV testing was almost unanimous, and 90% of participants reported that they would still want to be tested even if they were unable to receive HCV treatment. Baseline hepatitis C knowledge was poor; however, the brief educational intervention significantly improved knowledge and increased acceptability of testing when medical access issues were explicitly stated.
Despite inconsistencies in access to care and treatment, high-risk communities want to know their HCV status. Though baseline HCV knowledge was poor in this population, a brief on-site educational intervention improved both knowledge and acceptability of HCV testing and care. These data support the establishment of programs that utilize community-based screening, and also provide initial evidence for acceptance of the implementation of the recently expanded screening guidelines among marginalized communities.
PMCID: PMC3945609  PMID: 24512462
Health knowledge; Attitudes; Behaviors; Healthcare disparities; Hepatitis C; Patient education; Screening
12.  Improving the measurement of self-reported medication nonadherence 
Journal of clinical epidemiology  2010;64(3):250-254.
Medication nonadherence is a significant clinical problem in chronic disease management. Self-report measures have inadequate reliability and poor distributional properties. We demonstrate how two fundamental measurement issues have limited the usefulness of self-reported medication nonadherence measures and offer recommendations for improving measurement.
Study Design and Methods
We reviewed existing self-report measures of medication nonadherence in the context of hypertension, one of the most common chronic conditions in which medication nonadherence is a paramount concern. We evaluated these measures with regard to two issues: (1) conflation of causal indicators (which give rise to a latent construct) and effect indicators (which are determined by a latent construct), and (2) a lack of evidence regarding the stability of nonadherence over time.
Nonadherence measurement could be improved by using effect indicators to assess the extent of nonadherence and causal indicators to assess reasons for nonadherence. Moreover, nonadherence should be assessed longitudinally, so that recent developments in statistical modeling can illuminate the extent to which medication nonadherence is transient vs. stable.
Attention to these measurement issues can improve the assessment of self-reported nonadherence, thereby allowing more accurate conclusions to be drawn about medication-taking behavior and informing the development of improved interventions that target medication nonadherence.
PMCID: PMC3634915  PMID: 21194887
Adherence; Compliance; Psychometrics; Latent variable; Measurement; self-reports
Greater understanding of the mechanisms (mediators) by which behavioral change interventions work is critical to developing theory and refining interventions. Although systematic reviews have been advocated as a method for exploring mediators, this is rarely done. One challenge is that intervention researchers typically test only two paths of the mediational model: the effect of the intervention on mediators and on outcomes. We addressed this challenge by drawing information not only from intervention studies but also from observational studies, which provide data on associations between potential mediators and outcomes. We also reviewed qualitative studies of participants’ perceptions of why and how interventions worked. Using data from intervention (n= 37) and quantitative observational studies (n=55), we conducted a meta-analysis of the mediation effects of eight variables. Qualitative findings (n=6) contributed to more in-depth explanations for findings. The methods used have potential to contribute to understanding of core mechanisms of behavioral change interventions.
PMCID: PMC3155731  PMID: 21415244
systematic review; mediation analysis; meta-analysis; antiretroviral therapy; treatment adherence
14.  Mapping the Mixed Methods–Mixed Research Synthesis Terrain 
Mixed methods–mixed research synthesis is a form of systematic review in which the findings of qualitative and quantitative studies are integrated via qualitative and/or quantitative methods. Although methodological advances have been made, efforts to differentiate research synthesis methods have been too focused on methods and not focused enough on the defining logics of research synthesis—each of which may be operationalized in different ways—or on the research findings themselves that are targeted for synthesis. The conduct of mixed methods–mixed research synthesis studies may more usefully be understood in terms of the logics of aggregation and configuration. Neither logic is preferable to the other nor tied exclusively to any one method or to any one side of the qualitative/quantitative binary.
PMCID: PMC3467952  PMID: 23066379
mixed research synthesis; systematic review; aggregation; configuration
15.  Examining the impact of genetic testing for type 2 diabetes on health behaviors: study protocol for a randomized controlled trial 
Trials  2012;13:121.
We describe the study design, procedures, and development of the risk counseling protocol used in a randomized controlled trial to evaluate the impact of genetic testing for diabetes mellitus (DM) on psychological, health behavior, and clinical outcomes.
Eligible patients are aged 21 to 65 years with body mass index (BMI) ≥27 kg/m2 and no prior diagnosis of DM. At baseline, conventional DM risk factors are assessed, and blood is drawn for possible genetic testing. Participants are randomized to receive conventional risk counseling for DM with eye disease counseling or with genetic test results. The counseling protocol was pilot tested to identify an acceptable graphical format for conveying risk estimates and match the length of the eye disease to genetic counseling. Risk estimates are presented with a vertical bar graph denoting risk level with colors and descriptors. After receiving either genetic counseling regarding risk for DM or control counseling on eye disease, brief lifestyle counseling for prevention of DM is provided to all participants.
A standardized risk counseling protocol is being used in a randomized trial of 600 participants. Results of this trial will inform policy about whether risk counseling should include genetic counseling.
Trial registration Identifier NCT01060540
PMCID: PMC3464684  PMID: 22852560
Genetic testing; Type II diabetes; Weight loss
16.  An organizing framework for informal caregiver interventions: detailing caregiving activities and caregiver and care recipient outcomes to optimize evaluation efforts 
BMC Geriatrics  2011;11:77.
Caregiver interventions may help improve the quality of informal care. Yet the lack of a systematic framework specifying the targets and outcomes of caregiver interventions hampers our ability to understand what has been studied, to evaluate existing programs, and to inform the design of future programs. Our goal was to develop an organizing framework detailing the components of the caregiving activities and the caregiver and care recipient outcomes that should be affected by an intervention. In so doing, we characterize what has been measured in the published literature to date and what should be measured in future studies to enable comparisons across interventions and across time.
Our data set comprises 121 reports of caregiver interventions conducted in the United States and published between 2000 and 2009. We extracted information on variables that have been examined as primary and secondary outcomes. These variables were grouped into categories, which then informed the organizing framework. We calculated the frequency with which the interventions examined each framework component to identify areas about which we have the most knowledge and under-studied areas that deserve attention in future research.
The framework stipulates that caregiver interventions seek to change caregiving activities, which in turn affect caregiver and care recipient outcomes. The most frequently assessed variables have been caregiver psychological outcomes (especially depression and burden) and care recipient physical and health care use outcomes.
Based on the organizing framework, we make three key recommendations to guide interventions and inform research and policy. First, all intervention studies should assess quality and/or quantity of caregiving activities to help understand to what extent and how well the intervention worked. Second, intervention studies should assess a broad range of caregiver and care recipient outcomes, including considering whether expanding to economic status and health care use of the caregiver can be accommodated, to ease subsequent economic evaluations of caregiving. Third, intervention studies should measure a common set of outcomes to facilitate cross-time and cross-study comparisons of effectiveness.
PMCID: PMC3258201  PMID: 22107600
17.  Implementation of Antiretroviral Therapy Adherence Interventions: A Realist Synthesis of Evidence 
Journal of advanced nursing  2010;66(9):1915-1930.
This paper is a report of a synthesis of evidence on implementation of interventions to improve adherence to antiretroviral therapy.
Evidence on efficacy must be supplemented with evidence on how interventions were implemented in practice and on how that implementation varied across populations and settings.
Data Sources
Sixty-one reports were reviewed of studies conducted in the United States of America in the period 2001 to December 2008. Fifty-two reports were included in the final analysis: 37 reporting the effects of interventions and 15 reporting intervention feasibility, acceptability, or fidelity.
Review Methods
An adaptation of Pawson’s realist synthesis method was used, whereby a provisional explanatory model and associated list of propositions are developed from an initial review of literature. This model is successively refined to the point at which it best explains empirical findings from the reports reviewed.
The final explanatory model suggests that individuals with HIV will be more likely to enrol in interventions that protect their confidentiality, to attend when scheduling is responsive to their needs, and both to attend and continue with an intervention when they develop a strong, one-to-one relationship with the intervener. Participants who have limited prior experience with antiretroviral therapy will be more likely to continue with an intervention than those who are more experienced. Dropout rates are likely to be higher when interventions are integrated into existing delivery systems than when offered as stand-alone interventions.
The explanatory model developed in this study is intended to provide guidance to clinicians and researchers on the points in the implementation chain that require strengthening.
PMCID: PMC2923750  PMID: 20707822
literature review; implementation; Antiretroviral Therapy; Adherence; Interventions; Realist Synthesis of Evidence; Nursing; Pawson’s method
18.  Hypertension Improvement Project (HIP) Latino: results of a pilot study of lifestyle intervention for lowering blood pressure in Latino adults 
Ethnicity & health  2010;15(3):269-282.
To assess the feasibility of a culturally tailored behavioral intervention for improving hypertension-related health behaviors in Hispanic/Latino adults.
Feasibility pilot study in a community health center and a Latino organization in Durham, North Carolina (NC).
The culturally adapted behavioral intervention consisted of 6 weekly group sessions incorporating motivational interviewing techniques. Goals included weight loss if overweight, adoption of the Dietary Approaches to Stop Hypertension (DASH) dietary pattern, and increased physical activity. Participants were also encouraged to monitor their daily intake of fruits, vegetables, dairy and fat, and to record physical activity. Cultural adaptations included conducting the study in familiar places, using Spanish-speaking interventionist, culturally-appropriate food choices, and physical activity.
Main outcomes
Systolic blood pressure, weight, body mass index (BMI), exercise, and dietary pattern were measured at baseline and at 6 weeks follow-up. Qualitative evaluations of the recruitment process and the intervention were also conducted.
There were 64 potential participants identified via health care provider referrals (33%), printed media (23%), and direct contact (44%). Seventeen participants completed the intervention and had main outcome data available. Participants “strongly agreed/ agreed” that the group sessions provided them with the tools they needed to achieve weight loss, blood pressure control, and the possibility of sustaining the lifestyle changes after completing the intervention. At the end of the intervention, all physiological, diet, and exercise outcomes were more favorable, with the exception of fat. After 6 weeks, systolic blood pressure decreased an average of −10.4 ± 10.6 mmHg, weight decreased 1.5 ± 3.2 lbs, BMI decreased 0.3 ± 0.5, and physical activity increased 40 minutes per week.
Our findings suggest that lifestyle interventions for preventing and treating hypertension are feasible and potentially effective in the Hispanic/Latino population.
PMCID: PMC2888677  PMID: 20379894
Hypertension; Hispanic; Latino; non pharmacologic interventions; blood pressure control; weight loss; DASH dietary pattern; lifestyle intervention
19.  Bayesian data augmentation methods for the synthesis of qualitative and quantitative research findings 
Quality & quantity  2011;45(3):653-669.
The possible utility of Bayesian methods for the synthesis of qualitative and quantitative research has been repeatedly suggested but insufficiently investigated. In this project, we developed and used a Bayesian method for synthesis, with the goal of identifying factors that influence adherence to HIV medication regimens. We investigated the effect of 10 factors on adherence. Recognizing that not all factors were examined in all studies, we considered standard methods for dealing with missing data and chose a Bayesian data augmentation method. We were able to summarize, rank, and compare the effects of each of the 10 factors on medication adherence. This is a promising methodological development in the synthesis of qualitative and quantitative research.
PMCID: PMC3092168  PMID: 21572970
Meta-analysis; Meta-synthesis; Synthesis; Cross-design synthesis; Bayesian data augmentation; Missing data; Gibbs sampling
20.  A Systematic Review Comparing Antiretroviral Adherence Descriptive and Intervention Studies 
AIDS care  2009;21(8):953-966.
We examined the extent to which studies aimed at testing interventions to improve antiretroviral adherence have targeted the facilitators of and barriers known to affect adherence. Of the 88 reports reviewed, 41 were reports of descriptive studies conducted with U.S. HIV-positive women and 47 were reports of intervention studies conducted with U.S. HIV-positive persons. We extracted from the descriptive studies all findings addressing any factor linked to antiretroviral adherence and from the intervention studies, information on the nature of the intervention, the adherence problem targeted, the persons targeted for the intervention, and the intervention outcomes desired. We discerned congruence between the prominence of substance abuse as a factor identified in the descriptive studies as a barrier to adherence and its prominence as the problem most addressed in those reports of intervention studies that specified the problems targeted for intervention. We also discerned congruence between the prominence of family and provider support as factors identified in the descriptive studies as facilitators of adherence and the presence of social support as an intervention component and outcome variable. Less discernible in the reports of intervention studies was specific attention to other factors prominent in the descriptive studies, which may be due to the complex nature of the problem, individualistic and rationalist slant of interventions, or simply the ways interventions were presented. Our review raises issues about niche standardization and intervention tailoring, targeting, and fidelity.
PMCID: PMC2797126  PMID: 20024751
21.  Validation of a Questionnaire to Assess Self-Reported Colorectal Cancer Screening Status Using Face-to-Face Administration 
Digestive diseases and sciences  2008;54(6):1297-1306.
To assess the accuracy of an NCI-developed colorectal cancer screening questionnaire.
We conducted 36 cognitive interviews and made iterative changes to the questionnaire to improve comprehension. The revised questionnaire was administered face-to-face to 201 participants. The primary outcome was agreement between questionnaire responses and medical records for whether or not a participant was up-to-date for any colorectal cancer screening test.
Comprehension of descriptions and questions was generally good; however, the barium enema description required several revisions. The sensitivity of the questionnaire for up-to-date screening status was 94%, specificity was 63%, and concordance was 88%.
The modified questionnaire was highly sensitive for determining if a person was up-to date for any colorectal cancer screening test, although the specificity was low. Given the difficulty of obtaining all relevant records, self-report using this questionnaire is a reasonable option for identifying people who have undergone testing.
PMCID: PMC2754798  PMID: 18726152
colorectal neoplasms; mass screening; validation studies; questionnaires
22.  Defining and Designing Mixed Research Synthesis Studies 
Mixed research synthesis is the latest addition to the repertoires of mixed methods research and systematic review. Mixed research synthesis requires that the problems generated by the methodological diversity within and between qualitative and quantitative studies be resolved. Three basic research designs accommodate this diversity, including the segregated, integrated, and contingent designs. Much work remains to be done before mixed research synthesis can secure its place in the repertoires of mixed methods research and systematic review, but the effort is well worth it as it has the potential to enhance both the significance and utility for practice of the many qualitative and quantitative studies constituting shared domains of research.
PMCID: PMC2809982  PMID: 20098638
23.  Transforming Verbal Counts in Reports of Qualitative Descriptive Studies Into Numbers 
Reports of qualitative studies typically do not offer much information on the numbers of respondents linked to any one finding. This information may be especially useful in reports of basic, or minimally interpretive, qualitative descriptive studies focused on surveying a range of experiences in a target domain, and its lack may limit the ability to synthesize the results of such studies with quantitative results in systematic reviews. Accordingly, the authors illustrate strategies for deriving plausible ranges of respondents expressing a finding in a set of reports of basic qualitative descriptive studies on antiretroviral adherence and suggest how the results might be used. These strategies have limitations and are never appropriate for use with findings from interpretive qualitative studies. Yet they offer a temporary workaround for preserving and maximizing the value of information from basic qualitative descriptive studies for systematic reviews. They show also why quantitizing is never simply quantitative.
PMCID: PMC2784172  PMID: 19448052
mixed-methods research; qualitative; quantitizing; research synthesis
24.  On Quantitizing 
Quantitizing, commonly understood to refer to the numerical translation, transformation, or conversion of qualitative data, has become a staple of mixed methods research. Typically glossed are the foundational assumptions, judgments, and compromises involved in converting disparate data sets into each other and whether such conversions advance inquiry. Among these assumptions are that qualitative and quantitative data constitute two kinds of data, that quantitizing constitutes a unidirectional process essentially different from qualitizing, and that counting is an unambiguous process. Among the judgments are deciding what and how to count. Among the compromises are balancing numerical precision with narrative complexity. The standpoints of “conditional complementarity,” “critical remediation,” and “analytic alternation” clarify the added value of converting qualitative data into quantitative form.
PMCID: PMC2768355  PMID: 19865603
quantitizing; qualitative data; mixed methods research
25.  A Bayesian method for the synthesis of evidence from qualitative and quantitative reports: the example of antiretroviral medication adherence 
Bayesian meta-analysis is a frequently cited but very little-used method for synthesizing qualitative and quantitative research findings. The only example published to date used qualitative data to generate an informative prior probability and quantitative data to generate the likelihood. We developed a method to incorporate both qualitative and quantitative evidence in the likelihood in a Bayesian synthesis of evidence about the relationship between regimen complexity and medication adherence.
Data were from 11 qualitative and six quantitative studies. We updated two different non-informative prior distributions with qualitative and quantitative findings to find the posterior distribution for the probabilities that a more complex regimen was associated with lower adherence and that a less complex regimen was associated with greater adherence.
The posterior mode for the qualitative findings regarding more complex regimen and lesser adherence (using the uniform prior with Jeffreys' prior yielding highly similar estimates) was 0.588 (95% credible set limits 0.519, 0.663) and for the quantitative findings was 0.224 (0.203, 0.245); due to non-overlapping credible sets, we did not combine them. The posterior mode for the qualitative findings regarding less complex regimen and greater adherence was 0.288 (0.214, 0.441) and for the quantitative findings was 0.272 (0.118, 0.437); the combined estimate was 0.299 (0.267, 0.334).
The utility of Bayesian methods for synthesizing qualitative and quantitative research findings at the participant level may depend on the nature of the relationship being synthesized and on how well the findings are represented in the individual reports.
PMCID: PMC2764871  PMID: 19770121

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