Introduction to Health Services Research : A Self-Study Course
Module 6: Basic Components of a Study (Page 5 of 11)
Surveys | Cohort Studies | Case-Control Studies | Randomized Clinical Trials
Strengths and Pitfalls: Surveys
Surveys gather data to describe the demographics of a group, such as the Census; the health status of a group of people at a particular time; the utilization of medical services; or the knowledge, beliefs, and attitudes of people regarding health practices, such as cancer screening or HIV prevention.
Surveys are a major data collection method in health services research.
Surveys are a major data collection method in health services research. Researchers may collect data from interviews with patients, the public, clinicians, health care administrators, and others or from reports of hospital discharges, patient charts and medical records, disease registries, and billing documents.
Health services researchers usually assign names and acronyms to the surveys they develop. These surveys are tested for reliability and validity thoroughly before release to other researchers. Examples of named surveys include: the Sickness Impact Profile (SIP), the Deployment Risk and Resilience Inventory (DRRI), CAGE, and Longitudinal Studies of Child Abuse and Neglect.
Researchers ask people about their habits in surveys; e.g.,:
- Do you wear seat belts?
- Do you use condoms?
- Do you eat five vegetables a day?
Surveys give a snapshot of the present/past and tell us what people say they do/did. In examining surveys, librarians should look for response bias and not confuse cause and effect.
Survey research is extremely complex. Researchers must choose a sample of people to survey. Will the sample include the individual in a household or the entire household? Can a proxy answer questions accurately for a family member?
When comparing groups, they must acknowledge the different ways people will identify themselves, especially in terms of race and ethnicity. Racial and ethnic definitions vary widely; many nationalities are collapsed under broad terms, such as "Asian", which may hide differences between people of different cultures.
Whether surveyers want to assess patient preferences, diets, or health care utilization, they must ask questions that are clear and unbiased, a very difficult task! People often give different answers depending on the order of the questions, whether they are asked to agree or disagree with a statement, and how many possible choices they have for answers (Converse and Presser, 1986).
Don't forget that interview data depend on people's recall of past events and willingness to share their practices and beliefs with a stranger!
Incidence and Prevalence
Survey results are often analyzed in terms of rates that describe the number of existing cases (prevalence) of a disease or practice or the number of new cases (incidence) for a particular time. Interpretation of these rates requires some savvy.
For example, researchers track the incidence of cancer cases in a population over time. An increase in new cases may mean that more people are developing cancer because there is more exposure to the risk factor involved. Perhaps sun exposure increases in Australia and results in a real increase in melanoma.
On the other hand, an increase in breast cancer or prostate cancer cases may also result from changes in screening. When Betty Ford developed breast cancer, there was a dramatic rise in breast cancer rates due to increased mammography use and breast cancer diagnosis.
Because surveys capture people's behaviors and health status at the same time, it is impossible to conclude which factor is the cause or the effect. Heavy coffee drinkers may report more indigestion, but survey data do not allow readers to conclude that coffee causes indigestion (Abramson, 1988).
Surveys Provide Insights
While survey results often are difficult to interpret and generalize to other groups and time periods, they provide wonderful insights into the practices and health conditions of large groups of people as well as clues for future investigation into the impact of medical practices on health outcomes or the relationship between exposures and disease.
- This linked search contains examples of surveys used in health services research to assess health status. Can you find named instruments in the results? Where in the records are you likely to find named instruments?
- Visit HSRR and examine it for surveys and instruments. You can get additional information about this NLM database in the "Searching the Literature of Health Services Research" section of this online learning. One of the important health services research tools for measuring health status is the Sickness Impact Profile (SIP). Do a search on the SIP and examine the resulting hits in HSRR. Are the results specific to the SIP or are other instruments based on or related to the SIP included? What kinds of information can you find? How valuable would this database be for finding studies that you could adapt for your own work (assuming you get copyright permission from the author). Now try a second search on another named instrument that you're familiar with. Did you find any unique information in this search?
- Browse the HSRR database by title or source and examine several records. What fields does the database contain that would make it particularly useful to health services researchers?
- Does HSRR include any of the national longitudinal studies? An example of this kind of study is the "Health Interview Survey." Longitudinal studies developed by the National Center for Health Statistics and others are useful for the questionnaires they include in the Vital and Health Statistics publications.
- What is the difference, if any, between surveys, instruments and questionnaires?
- Have you or someone you know ever taken part in a health survey, either through a national research project such as the National Health Interview Survey, or through BRFSS (Behavioral Risk Factor Surveillance System)? What did you learn from the process that will help you with your work? What do you think you would learn (if you have not participated in a health survey)?