Health Education as a Discipline · 8 min read
Health Data, Research Methods and Needs Assessment
Epidemiology is the study of the distribution and determinants of health-related conditions in populations and the application of that study to the control of health problems. Health educators use epidemiological data to identify priority problems, justify programs, select content and evaluate results. Sound practice depends on reading data correctly and on drawing it from valid, reliable sources.
Epidemiology Vocabulary
| Term | Definition |
|---|---|
| Incidence | Number of new cases of a condition in a population during a specified period |
| Prevalence | Total number of existing cases, new and old, at a point in time or during a period |
| Morbidity | Illness, injury or disability in a population |
| Mortality | Death in a population |
| Rate | Number of events divided by the population at risk in a period, expressed per 1,000 or 100,000 people |
| Risk factor | Characteristic, behavior or exposure that raises the probability of a condition; modifiable or nonmodifiable |
| Protective factor | Characteristic or condition that lowers the probability of a negative health outcome |
| Life expectancy | Average number of years a person is expected to live, based on current death rates |
| Relative risk | Risk of a condition in an exposed group divided by the risk in an unexposed group |
| Endemic | Constant, expected presence of a disease in a geographic area or population |
| Epidemic | Occurrence of cases clearly above the expected level in an area; a localized epidemic is an outbreak |
| Pandemic | Epidemic that has spread across several countries or continents and affects many people |
A relative risk of 1.0 means that exposed and unexposed groups have the same risk. A value above 1.0 indicates higher risk with exposure (2.0 means twice the risk), and a value below 1.0 suggests a protective effect. Rates permit fair comparison between populations of different sizes; raw counts do not. Incidence reflects how quickly new cases arise, while prevalence reflects the total burden and is most useful for chronic conditions.
Research Methods
Quantitative research collects numerical data through surveys, measurements and experiments and analyzes it statistically to answer questions of how many or how much. Qualitative research collects words and observations through focus groups, interviews and open-ended questions to explain why and how. Mixed-methods studies combine both, for example by following a student survey with focus groups that interpret the results.
| Design | What it does | Strength and limitation |
|---|---|---|
| Cross-sectional survey | Measures exposures and outcomes in a sample at one point in time | Quick; shows prevalence. Cannot establish time order or cause |
| Cohort study | Follows a group over time, comparing those with and without an exposure | Shows incidence and sequence. Lengthy and costly |
| Case-control study | Compares people who have a condition with people who do not, looking back for exposures | Efficient for rare conditions. Prone to recall bias |
| Randomized controlled trial | Assigns participants at random to an intervention or a control group | Strongest evidence of cause. Costly; not always ethical or feasible |
| Focus group | Moderated discussion with a small group, typically 6 to 12 people | Reveals attitudes and language. Not generalizable |
| Interview | One-on-one structured or open-ended questioning | Depth of detail. Time intensive |
| Observation | Systematic recording of behavior in a natural setting | Records actual behavior. Observer presence may alter it |
A sample is the subset of a population that is studied. Random (probability) sampling gives each member a known chance of selection and supports generalization; convenience samples do not. Bias is systematic error. Selection bias occurs when the sample differs from the population, recall bias when memory is inaccurate, social desirability bias when respondents give answers they think are acceptable, and nonresponse bias when those who decline differ from those who take part. Anonymous surveys reduce social desirability bias on sensitive topics.
Correlation means that two variables change together; it does not show that one causes the other. A third factor, called a confounding variable, may explain the association, or the direction of effect may be reversed. Causal claims require correct time order, a strong and consistent association, a dose-response relationship, biological plausibility and, ideally, experimental confirmation.
Valid and Reliable Data Sources
The Youth Risk Behavior Surveillance System (YRBSS), managed by the CDC, is the principal source of data on adolescent health behavior. It includes a national school-based survey of students in grades 9 to 12 conducted every two years, together with state, territorial, tribal and large urban district surveys. Responses are anonymous, voluntary and self-reported. The system monitors six categories of priority health-risk behaviors and also tracks obesity and asthma.
- Behaviors that contribute to unintentional injuries and violence
- Sexual behaviors related to unintended pregnancy and sexually transmitted infections, including HIV
- Alcohol and other drug use
- Tobacco use
- Unhealthy dietary behaviors
- Inadequate physical activity
| Source | Population and method | Typical use |
|---|---|---|
| Youth Risk Behavior Surveillance System | High school students; anonymous school-based survey every two years | Prevalence of priority risk behaviors among youth |
| School Health Profiles | Principals and lead health education teachers in secondary schools; every two years | School health policies and practices by state and large district |
| School Health Policies and Practices Study | Periodic national survey at state, district, school and classroom levels | National picture of school health policies and programs |
| Behavioral Risk Factor Surveillance System | Adults aged 18 and older; state-based telephone survey | State-level adult risk behaviors, chronic conditions, preventive service use |
| National Health and Nutrition Examination Survey | Children and adults; interviews plus physical examinations and laboratory tests | Measured data such as body mass index, blood pressure, nutrient status |
| National Health Interview Survey | Households; interview | Illness, disability, insurance coverage, access to care |
| National Survey on Drug Use and Health | People aged 12 and older; household interview | Substance use and mental health indicators |
| Monitoring the Future | Students in grades 8, 10 and 12; annual school survey | Trends in drug use, perceived risk and disapproval |
| CDC WONDER | Online query system for many public health data sets | Custom tables of deaths, births and disease by place and group |
| National Vital Statistics System | Birth and death records collected by states | Birth rates, leading causes of death, life expectancy |
| Healthy People | National objectives issued each decade by the U.S. Department of Health and Human Services | Measurable targets and benchmarks for program goals |
| County health rankings | County-level measures of health outcomes and the conditions that shape them, compared within each state and nationally | Local comparison and priority setting |
| State and local health departments | Disease surveillance, vital records, community health assessments | Local data for planning and justification |
School-level records add local detail: attendance and chronic absenteeism data, school nurse visit logs, discipline and counseling referrals, fitness assessment results and school meal participation. Comparing local findings with state and national benchmarks shows whether a problem is larger or smaller than expected and strengthens the case for a program.
School Health Needs Assessment
A needs assessment is a systematic process for identifying the gap between the current and the desired health status of a population and for setting priorities among the needs found. A thorough assessment also inventories assets and capacity, such as staff expertise, facilities and community partners, so that plans build on existing strengths.
| Tool | Purpose and features |
|---|---|
| School Health Index | CDC self-assessment and planning guide. A school team scores policies and programs across the components of school health and writes an improvement plan |
| Health Education Curriculum Analysis Tool (HECAT) | CDC tool for analyzing health education curricula against national standards and the characteristics of effective curricula |
| Physical Education Curriculum Analysis Tool | CDC tool for analyzing written physical education curricula against national physical education standards |
| Surveys and questionnaires | Collect self-reported knowledge, attitudes and behaviors efficiently from many students, families or staff |
| Focus groups | Explore perceptions, vocabulary and reasons behind behaviors in a small moderated group |
| Key-informant interviews | Interviews with people who have special knowledge of the population, such as the school nurse, counselor or a pediatrician |
| Nurse and attendance records | Existing records showing patterns of illness, injury, chronic conditions and absenteeism |
| Community forums | Open public meetings that gather concerns; may overrepresent the most vocal participants |
- YRBSS: CDC, high school students, every two years, six priority risk behavior categories, self-reported prevalence data.
- BRFSS surveys adults by telephone; NHANES is the survey that adds physical examinations and laboratory tests.
- The School Health Index assesses a school's policies and programs; the HECAT analyzes a health education curriculum.
- Reliability is consistency; validity is accuracy. Random sampling supports generalization.
- A randomized controlled trial provides the strongest evidence of cause; cross-sectional surveys show association at one point in time.
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