Theories give the community/public health nurse a structured way to assess a community, explain why problems occur, choose interventions, and evaluate results. Community practice draws on two kinds of theory:

• Nursing theories and models applied to individuals, families, groups, and communities (Neuman, Orem, Roy)
• Theories from other disciplines (general systems theory, social exchange theory, ecological models) and public health practice models (Community-as-Partner, the Public Health Intervention Wheel)

Health behavior theories used in health education (Health Belief Model, Transtheoretical Model, Pender's Health Promotion Model) are covered in Topic 13.

General systems theory (Ludwig von Bertalanffy) — a community is an open system that constantly exchanges energy, matter, and information with its environment.

A change in one subsystem affects the others — for example, a factory closure (economy) raises uninsured rates (health) and school stress (education).

Social exchange theory (George Homans) — people act to gain rewards and avoid costs; social behavior is an exchange of rewards (tangible, social, or psychological) and costs. Homans's propositions:

• Success proposition — behavior that is rewarded is likely to be repeated
• Stimulus proposition — if a past situation led to reward, similar situations will prompt the same behavior
• Value proposition — the more valuable the reward, the more likely the behavior
• Deprivation–satiation proposition — the more often a person has recently received a reward, the less valuable additional units become
• Aggression–approval proposition — when an action does not receive the expected reward or receives unexpected punishment, the person becomes angry; when it receives the expected reward (or more) or avoids expected punishment, the person is pleased (approval)
• Rationality proposition — people choose the alternative with the greatest expected value (value of the result × probability of getting it)

Community application: make healthy behavior rewarding and reduce its costs (time, money, discomfort) — for example, immediate small incentives for attending a smoking cessation program, or recognition that keeps volunteers engaged. Limitation: the theory emphasizes external rewards and costs and pays little attention to intrinsic motivation, values, and responsibility.

Neuman Systems Model (Betty Neuman) — the client system (individual, family, group, or community) is a set of five interacting variables (physiological, psychological, sociocultural, developmental, spiritual) around a basic structure (core energy resources), protected by concentric lines:

Stressors are intrapersonal, interpersonal, or extrapersonal. Nursing interventions are prevention as intervention:

• Primary prevention — before a reaction: reduce the chance of meeting a stressor and strengthen the flexible line of defense (e.g., immunization, health education)
• Secondary prevention — after a reaction occurs: early detection and treatment of symptoms, strengthening the lines of resistance to protect the basic structure (e.g., screening and prompt treatment)
• Tertiary prevention — after treatment: support reconstitution, the return to stability (which may be at a higher or lower level than before), and prevent recurrence (e.g., rehabilitation)

Orem's Self-Care Deficit Nursing Theory (Dorothea Orem) — people are capable of self-care; nursing is needed when self-care demand exceeds self-care agency (a self-care deficit).

Nursing systems:

• Wholly compensatory — the nurse (or a dependent-care agent) does everything; the client cannot act (e.g., unconscious client)
• Partly compensatory — nurse and client share care (e.g., a client with arthritis who can bathe but needs help with foot care)
• Supportive-educative — the client can perform self-care but needs teaching, guidance, and support (common in community practice)

A dependent-care agent (often a family member) provides care for someone who cannot meet their own needs. The goal of nursing is to develop and restore the client's own self-care ability.

Roy Adaptation Model (Callista Roy) — the person or group is an adaptive system responding to stimuli:

• Focal stimulus — the one most immediately confronting the person (e.g., a new diagnosis of hypertension)
• Contextual stimuli — all other factors present that contribute (e.g., high-sodium diet, job stress)
• Residual stimuli — factors whose effects are unclear (e.g., beliefs about medication)

Coping processes (regulator and cognator) produce behavior in four adaptive modes: physiologic–physical, self-concept–group identity, role function, and interdependence. Responses are adaptive (promote integrity and goals) or ineffective. The adaptation level may be integrated, compensatory, or compromised. Roy's six-step nursing process: (1) assessment of behavior, (2) assessment of stimuli, (3) nursing diagnosis, (4) goal setting, (5) intervention (managing stimuli), (6) evaluation.

Public health practice models

• Community-as-Partner model (Anderson and McFarlane) — a community assessment wheel: the community core (people: history, demographics, values, beliefs) surrounded by eight subsystems — physical environment; health and social services; economics; transportation and safety; politics and government; communication; education; recreation. Stressors penetrate lines of defense and resistance (derived from Neuman), and the nurse intervenes with the community as an equal partner
• Public Health Intervention Wheel (Minnesota Department of Health) — 17 population-based interventions grouped in five "wedges" (e.g., surveillance, disease and health event investigation, outreach, screening, case-finding; referral and follow-up, case management, delegated functions; health teaching, counseling, consultation; collaboration, coalition building, community organizing; advocacy, social marketing, policy development and enforcement), applied at three levels: individual/family, community, and systems
• Social-ecological model — health is shaped by nested levels: individual, interpersonal, organizational, community, and public policy; the most effective programs act on several levels at once

• Choose a framework that fits the question and state it explicitly in assessments and program plans
• Collect data systematically according to the model (e.g., all eight Community-as-Partner subsystems)
• Use the model's concepts to write diagnoses and goals (e.g., Roy: "ineffective role function related to ...")
• Evaluate programs with feedback loops and adjust
• Involve community members as partners, not passive recipients

• Theories guide but do not replace legal scope: interventions must stay within the state Nurse Practice Act and public health law
• Incentive-based programs (social exchange) must be fair, noncoercive, and respectful of autonomy
• Community assessment data must be collected and stored confidentially; small-area data can identify individuals
• Partnership models reflect ethical commitments to respect, participation, and justice

Case 1 — Orem. A home health nurse visits a client newly diagnosed with type 2 diabetes who can learn but lacks knowledge. She uses the supportive-educative system to teach glucose monitoring. The learning need is a health-deviation requisite. Why: the need arises from the illness and its treatment, not from a life stage.

Case 2 — Neuman. A PHN runs a free blood pressure screening program. In Neuman's terms this is secondary prevention because it detects a reaction (disease) that has already occurred. Why: primary prevention acts before a reaction and strengthens the flexible line of defense; secondary prevention strengthens the lines of resistance.

Case 3 — Systems theory. A program evaluation shows low attendance; the team moves sessions to evenings. Why: evaluation data acting as feedback adjust inputs and processes.

Case 4 — Homans. Participants who receive immediate small rewards (a healthy food voucher) at each session attend more consistently. Why: the success and value propositions predict that rewarded behavior is repeated.

• Calling a new illness diagnosis a "developmental" requisite in Orem's theory — it is health-deviation
• Mixing up Neuman's lines: flexible (outer buffer) → normal (usual wellness) → lines of resistance (activated after penetration)
• Saying primary prevention strengthens the lines of resistance — it strengthens the flexible line of defense; lines of resistance belong to secondary prevention
• Confusing Roy's focal (immediate) with contextual (contributing) stimuli
• Treating the community as a closed system
• Labeling program results as "process" — outputs and outcomes are results; process is the activity
• Assuming Homans explains all health behavior — intrinsic motivation is poorly addressed

• Systems theory: input → throughput → output → feedback; community is an open system; boundary, entropy, equifinality
• Homans: success, stimulus, value, deprivation–satiation, aggression–approval, rationality propositions
• Neuman: flexible line of defense → normal line of defense → lines of resistance → basic structure
• Neuman prevention: primary strengthens the flexible line of defense; secondary strengthens the lines of resistance; tertiary supports reconstitution
• Orem: universal, developmental, health-deviation requisites; wholly compensatory, partly compensatory, supportive-educative systems
• Roy: focal, contextual, residual stimuli; four modes — physiologic, self-concept, role function, interdependence
• Community-as-Partner: community core + eight subsystems
• Intervention Wheel: 17 interventions, three levels (individual/family, community, systems)
• Social-ecological model: act at several levels at once