HS 250 Exam 4

Discuss the Feasibility of the Intervention

For the sample intervention, also discuss the political and economic feasibility of implementing the policy.

Identify a Policy Intervention

Identify one policy intervention that has been used or proposed to address the public health problem you chose. Assess the appropriateness, comprehensiveness, and effectiveness of the intervention.

How many children and adolescents are at risk for becoming overweight or are overweight.

Nearly 20 percent

Propose the Next Steps

On the basis of your discussion, propose and discuss the next steps needed in the realms of research, interventions, and policy to address the problem.

Independent variables for Planet Health

— Active independent variable: Planet Health intervention — Attribute independent variables: age, sex, and race/ethnicity

Dependent variables for Planet Health

— Body mass index (BMI) (as a function of height and weight) — Triceps skinfold (TSF) — Television and video viewing — Moderate/vigorous physical activity levels — Intake of fruits/vegetables — Proportion of energy from fat/saturated fat — Total energy intake

Planet Health Program components:

— Training and wellness sessions for teachers — Classroom lessons incorporated into math, science, language arts, and social studies — "Media-reduction campaign" — Physical education units

Analysis of the Intervention: Appropriateness

•Addresses the primary determinants of obesity— physical activity and diet •Addresses the determinant of television viewing by aiming to reduce television use and increase activity time •Aimed at appropriate population demographics (adolescents in middle school)

Randomization

•Allocating a set of subjects to either experimental or control group by random procedure •Purpose: Ensure internal validity —Eliminate bias from self-selection —Eliminate alternative explanations of the intervention's effect

Efficiency Analysis

•Analysis of the overall direct and indirect costs and benefits of an intervention that can be used to compare interventions to similar goals •Cost-benefit analysis—a program's benefits are compared with its direct and indirect costs in monetary terms •Cost-efficiency analysis—a program's benefits are compared with its costs, but only the costs of the program are monetized —Benefits expressed in outcome units —Quality-adjusted life years—quality of life for duration of surviva

Simulations

•Application of models over a specified period to demonstrate:— Structure of the system — Effects on system components when one or more components are altered •Strengths: — High economic feasibility — Ability to magnify phenomenon — Ability to manipulate conditions — Safe alternative •Weakness: — Artificiality

Evaluation Research

•Assesses effectiveness of a program or how well a policy can be applied to other settings •Often necessary to fulfill funding requirements •Typically conducted by an objective investigator that has no involvement in implementation •May utilize quantitative and qualitative methods •Includes needs assessments, process evaluations, and outcome evaluations

Cross-sectional Surveys

•Characteristics of a population are examined at a specific point in time •Limitations: — Cannot reveal causal relationships — Risk of bias —reliance on participant recall

Laboratory Experiments

•Conducted in artificial settings where researchers have control over: — Random allocation — Degree of intervention applied •Rarely used in health policy research

Field Experiments

•Conducted in natural, real-life settings •Strengths:High external validity — Yield generalizable results — Suitable for applied research •Weaknesses: Low level of control — Random assignment may not be possible

Analysis of the Intervention: Comprehensiveness

•Covers a diverse student population in terms of age, gender, and race/ethnicity •Addresses actionable determinants of childhood obesity •Invites parents and family members to participate with students (through voluntary additional lessons)

Dependent variable

the variable examined to determine whether its observed value changes in the presence of, or when exposed to, the independent variable

Unit of Analysis

•Depends on research goals •May include: — Individuals — Groups — Incidents, events, activities — Research setting itself •Determines data collection, analysis, and reporting strategies

Independent variable

the treatment, characteristic, exposure, etc., that is being examined to determine its effect

In-depth interviews can be conducted with individual participants or can be conducted with a group

Focus group — In-depth interview conducted with a group of participants — Consists of 6 to 12 participants engaged in a guided discussion

Defining the Problem

Briefly define the nature and scope of the public health problem chosen. Discuss the most important individual, sociocultural, political, and economic determinants of the problem.

Assess the Intervention

For the intervention you selected, provide a summary review of previous evaluations, if available. Describe and critique an existing evaluation or suggest your own evaluation.

Quantitative Methods

Essential elements: Experimental and control groups, Randomization, Pre- and post-testing , Application of an intervention Includes experimental and quasi-experimental research

in-depth interview strengths and weaknesses

Strengths: — Flexibility in how and where conducted — High face validity — Low associated costs •Limitations: — Limited available time — Less control — Difficult to analyze

Obesity is a major risk factor for

heart disease, certain cancers, stroke, diabetes, hypertension, sleep apnea, pulmonary dysfunction, osteoporosis, hypercholesterolemia, and asthma

Experimental research

studies causal relationships between independent and dependent variables

Qualitative Methods

•Embody observations and analyses captured in statements and concepts from open-ended responses and participants' quotes •Goal: gain individual perspectives to gain in-depth insight into a complicated problem •Types: — Participant observation — In-depth interview — Case study

Next Steps in Policy

•Ensure sustained support for Planet Health. •Ensure priority funding for schools that may have limited budgets or serve poor socioeconomic populations. •Address commercial messaging on obesity (e.g., a ban on food product advertising targeted to children, mandatory marketing about nutrition and fitness that is equal in time to junk food ads, or a prohibition of the use of children's characters to promote unhealthy food).

Outcome Evaluation

•Examines the impact of a service, program, or policy and assesses the extent to which it is successful in reaching its goals •Compares to status quo or alternative •Assesses according to outcome measures: mortality, morbidity, quality of life, health-related behavior •Medical outcomes research—outcome evaluation that examines the comparative effectiveness of available treatments for a patient with specific characteristics

Experimental and Control Groups

•Experimental—participants who receive the intervention •Control—participants who do not receive the intervention — True control group—made equivalent by random assignment — Comparison group—nonequivalent assignment •Purpose: — Assess true impact of the intervention — Account for events outside the intervention

Threats to External Validity

•External validity: generalizability of the study •Several threats to external validity: — Reactive/situational effects of testing: Students' awareness of learning from the Planet Health program may have been heightened during the study time. — Threats from multiple treatments: Health promotion campaigns could have existed within the community, biasing study results to make them less generalizable to the general population.

Data Collection

•In qualitative studies, the researcher must: — Prevent leading — Remain neutral — Have good working knowledge of topic of interest •Advances in technology: — Aid in conducting, transcribing, and coding qualitative responses — Increase ease of participation

In-Depth Interview

•Informal conversational interview — Conducted during the course of an observational study and does not follow prescribed set of questions •General interview guide approach — Interviewer follows an outline of topics but has flexibility in how and when to ask questions •Standardized open-ended interview — Interviewer follows a prescribed set of standardized questions for every subject in the same order

Threats to Internal Validity

•Internal validity: likelihood that observed outcomes are actually due to the active independent variables •Randomized design granted a high degree of internal validity to this study •Regardless of strengths, there were some threats to internal validity: — Low level of control over extraneous variables in the students' environment (e.g., competing health education campaigns) — Use of student self-report on dietary intake and physical activity

Natural Experiments

•Lack of control over experimental conditions •Must rely on naturally occurring events in which different levels of exposure exist

Literature Findings of Obesity

•Lower health-related quality of life (e.g., poor school performance) •Lower social functioning •Poor emotional health •Depression •Higher burden of disability into adulthood

Planet Health

•Main goal: to lower the prevalence of obesity among middle school students •Objectives: — Reduce television viewing time — Decrease consumption of unhealthy food choices — Increase consumption of healthy food choices — Increase physical activity

Process Evaluation

•Monitors and improves ongoing programs or policies •Examines components that are essential to implementation and success •Ensures proper and efficient resource allocation and compliance with legal and regulatory requirements

Survey Research

•Most common method of data collection •Survey research aims to measure distribution of results/characteristics among a large study sample through: — Use of a systematic method to collect data directly from respondents — Subsequent quantitative analysis of data •Survey types: — Cross-sectional — Longitudinal

Qualitative Study Design

•Much like quantitative research, the design should begin with a literature review •Must ensure access to participants and research setting •Must develop relationship and work closely with program staff •In design of the study, researchers must consider: — Unit of analysis, sampling procedures, researcher's role, ethical implications, data collection, and analysis strategy

Ethical Implications

•Must be considered when designing and implementing qualitative research •Must consider: — Potential risks to participant — Legal liabilities

Next Steps in Research

•Need for continued evaluative research of Planet Health and similar programs •Need for long-term cohort data of Planet Health and similar programs •Need for best practices database to compile data on various school-based health promotion programs

Participant Observation

•Observational research—researchers become part of the group or setting of interest — Open participation—investigator's role is known — Disguised—only leaders are aware that observation is occurring •Researcher directly observes physical, social, and human environment; formal and informal interaction; and unplanned activities

Political Feasibility

•Planet Health, which is evidence based, generally feasible in its implementation and delivery, cost-effective, and socially acceptable, is a unique alternative that is palatable to a wide range of stakeholders. •The current political environment is supportive of programs aimed at reducing childhood obesity. •The ultimate political success of Planet Health depends on the formation of coalition groups comprising a wide array of stakeholders.

Administrative Feasibility

•Program enables schools to try creative or collaborative solutions to administrative challenges they may face. •Teachers are fully responsible for program implementation and administration and can tailor program materials to their classrooms. •There are many training options for teachers. •Administration is not overly burdensome. •School administrators could explore nonmonetary incentives to offer to teachers for participation.

Economic Feasibility

•Programs such as Planet Health would be most successful if supported by a combination of government funding and funding from public/private organizations. •Federal and state governments have a financial and moral incentive to support initiatives aimed at childhood obesity. •An independent cost-benefit analysis of Planet Health found that potential benefits far outweigh startup/ maintenance costs.

Determinants of Obesity

•Proximate determinants: — Biological, demographic, behavioral (physical activity and diet) •Midlevel distal determinants: — Home, neighborhood, school •Macro-level distal determinants: — Social, political, economic

Quasi-Experimental Research

•Randomization may not be practical or ethical •Quasi-experimental research applies an intervention but does not randomly assign participants •To ensure comparability between study groups: — Propensity score matching — Matching — Stratified random sampling

Study Design

•Randomized pretest-post-test control group experimental design. •Planet Health curriculum was administered to students whose school enrollments in grade 6 or 7 began in fall 1995.

Analytic Strategy

•Researchers employed the generalized estimating equation regression method to: — Adjust for individual-level confounders within clusters (schools) — Account for correlations between responses within schools •The following variables were controlled for in the regression models: — Race/ethnicity, age, BMI, TSF, intervention status, and randomization pair indicators •Regression analyses were used to predict changes in behavioral measures and assess the causation level between the intervention and significant changes in behavior.

Role of Researchers

•Researchers must decide the degree to which they reveal themselves during the study •Role must be defined in preliminary stages of the study •May range from solely observation to full participation

Analysis Strategy

•Researchers must: — Produce detailed descriptions of subjects' perspectives — Explain and interpret — Assign significance to results •Coding: Researcher must identify each unique response, theme, or concept

Selection of the Intervention-Obesity

•Schools are an ideal setting for obesity prevention interventions. •The literature shows mixed or modest results from school-based health interventions. •Planet Health is currently one of the most effective programs targeted to obesity.

Analysis of the Intervention: Effectiveness

•Significant outcomes among both girls and boys in the intervention schools: — Amount of television viewing was reduced •Significant outcomes among girls only in the intervention schools: — Decrease in obesity prevalence — Increase in consumption of fruits/vegetables — Reduction in dietary energy intake •No significant outcomes among boys only in the intervention schools

Evaluation Research strengths and weaknesses

•Strengths: — Potential to impact policy — Practical and tangible evidence •Weaknesses: — Selection bias — Differential attrition — Limited generalizability — Scope limited by time, financial constraints, and political climate

Longitudinal Surveys

•Survey conducted at repeated intervals over a predetermined length of time with the same or similar sample •Trend study—series of cross-sectional studies on repeated samples •Panel study—series of repeated data collection among the same sample •Limitations: — Expensive to conduct — Prone to attrition

Pre- and Post-Testing

•Testing or observing experimental and control groups before (pretest) and after (post-test) the intervention •Time series test: used to measure the long-term impact — Measurements taken at equal intervals before and after the program •Purpose: — Assess impact of intervention by comparing pre- and post-test results — Can eliminate the need for a control group

Ensuring Rigor

•The research question, theoretical framework, methods, and context of the research must be clearly defined •The study design must reflect the implications of the selected sample •Data collection methods, data types and sources, and analysis methods must be clearly defined •Triangulation •Researchers must provide necessary information and data to support interpretations

Sampling

•Typically determined on accessibility in qualitative research •Must rely on other methods to select a representative sample: — Purposive sampling—selection of a small sample of subjects whose key characteristics are similar to those of the target population — Other methods: time sampling, typical case sampling, extreme case sampling, intensity sampling, and stratified purposeful sampling

Case Study

•Use of multiple sources of data to gain an in-depth understanding of an entity or a phenomenon •Researchers utilize a variety of data collection methods, such as: — Surveys — Observation — Interviews — Review of administrative records •Cases—may be defined as a person, an event, a program, a community, etc.

Needs Assessment

•Used to identify areas of weakness or deficiency at the organization or community level •Obtains data from variety of sources to identify problems, prioritize problems, and determine which outcomes to pursue •Organization level: — Identify inadequacies and inefficiencies and propose solutions •Community level: — Examine community characteristics and their relationship to health systems to identify gaps in services