Nursing Evidence-Based Practice and Research Methods: PICO, Hypotheses, Variables

What is evidence-based practice (EBP)?

Clinical decision-making that integrates the best available evidence, clinical expertise, and the individual patient's values, preferences, and circumstances.

What are the three components of EBP?

Best available evidence; clinical expertise; patient values, preferences, and circumstances. All influence the decision.

Why can the best research evidence require adaptation for a particular patient?

The patient may have different goals, contraindications, resources, or preferences. Clinical judgment and shared decision-making help adapt evidence.

How does research differ from EBP?

Research systematically generates or refines knowledge; EBP finds, appraises, and applies available evidence to clinical decisions.

How does quality improvement (QI) differ from research?

QI primarily improves a local process or outcome; research aims to produce knowledge that may be applicable beyond the setting.

What is research utilization, and how is it related to EBP?

Research utilization critically evaluates and applies research findings. EBP is broader: it also includes expertise, patient preferences, context, and other evidence.

A hospital changes its own discharge workflow to reduce local delays. What is its primary process?

Quality improvement, because the primary aim is improvement of a local process.

A nurse combines evidence, clinical judgment, and a patient's preferences. What process is this?

Evidence-based practice (EBP).

What is a typical EBP sequence?

Ask a focused question; search; critically appraise; synthesize; adapt to setting and patient; implement; evaluate and share findings.

What is the difference between critical appraisal and synthesis?

Appraisal evaluates the quality and relevance of individual evidence; synthesis combines and interprets findings across sources.

What is an evidence hierarchy?

A framework that ranks types of evidence for a particular question. Design quality and relevance still matter, and rankings vary with the question and framework.

What is a common approximate evidence hierarchy for intervention questions?

Systematic reviews of high-quality randomized trials; individual randomized trials; nonrandomized intervention studies; observational studies; descriptive or qualitative studies; expert opinion. Check your professor's specific pyramid for exact labels and levels.

Why is qualitative research not automatically weak evidence?

It can be especially appropriate for questions about meaning, culture, and lived experience. The best evidence type depends on the question.

What is a systematic review?

A structured search, selection, and critical appraisal of relevant studies to answer a focused question. It may or may not include a meta-analysis.

What is a meta-analysis?

A statistical combination of compatible quantitative findings from multiple studies, commonly within a systematic review.

What is a qualitative meta-synthesis?

An integration and interpretation of findings or themes across qualitative studies.

Does a systematic review always include a meta-analysis?

No. A systematic review is a structured review; meta-analysis is a statistical technique that may be included when appropriate.

What is the difference between no evidence of benefit and evidence of no benefit?

No evidence of benefit means evidence is insufficient to establish benefit; evidence of no benefit means adequate evidence suggests little or no benefit.

What does PICO stand for?

P = population or problem; I = intervention or exposure of interest; C = comparison; O = outcome.

What does T in PICOT mean?

Time frame, when relevant to the question. It is not required in every question.

In a PICO question, what is the population?

The patient group or problem of interest, such as hospitalized adults at risk of falling.

In a PICO question, what is the intervention?

The treatment, action, exposure, or area of interest being considered, such as hourly rounding.

In a PICO question, what is the comparison?

The alternative against which the intervention is considered, such as usual care. A comparison may be absent if the question does not require one.

In a PICO question, what is the outcome?

The result of interest, ideally defined in measurable terms, such as fall rate per 1,000 patient-days.

In hospitalized adults, does hourly rounding versus usual care reduce falls? Identify P, I, C, and O.

P: hospitalized adults; I: hourly rounding; C: usual care; O: falls or fall rate.

What does PCC stand for, and when is it useful?

Population, Concept, Context. It is useful for broad or scoping questions, such as mapping what is known about a topic in a setting.

Can a qualitative question omit an intervention and comparison?

Yes. Some qualitative questions focus on the population and an experience or outcome rather than an intervention and comparison.

What is a research question?

A clear statement of what a study seeks to answer.

What is a hypothesis?

A testable prediction about a relationship or difference between variables.

What is a null hypothesis (H0)?

A statement that there is no difference or association in the population as specified by the hypothesis.

What is an alternative or research hypothesis?

A statement that a difference or association exists; it can be directional or nondirectional.

What is a directional hypothesis?

A prediction stating the direction of a relationship or difference, such as an intervention group having lower anxiety.

What is a nondirectional hypothesis?

A prediction that a difference or association exists without stating its direction.

The researcher predicts that scores will differ between two groups, without saying which is higher. What hypothesis is this?

A nondirectional alternative hypothesis.

The researcher predicts fewer falls with hourly rounding. What hypothesis is this?

A directional alternative hypothesis because the predicted direction is fewer falls.

Does failing to reject the null hypothesis prove that there is no effect?

No. The study may lack power or have substantial uncertainty. Failure to reject is not proof of equivalence or no effect.

What is an independent variable (IV)?

The presumed influencing variable, predictor, exposure, or researcher-manipulated intervention.

What is a dependent variable (DV)?

The outcome measured to determine how it varies with the independent variable.

In a study of music therapy and anxiety, what are the independent and dependent variables?

IV: music therapy versus comparison. DV: anxiety, measured using the specified instrument.

What is an extraneous variable?

A variable other than the main variable of interest that may influence the outcome.

What is a confounding variable?

A variable related to both the exposure or group and the outcome that can distort the observed relationship.

How might illness severity confound a treatment study?

If one treatment group is sicker and illness severity affects recovery, differences in recovery might partly reflect severity instead of treatment.

How can researchers reduce confounding?

Methods include random assignment, restriction, matching, and statistical adjustment. These reduce some threats but do not guarantee that all confounding is eliminated.

What is a conceptual definition?

An explanation of the abstract meaning of a concept; for example, anxiety as a feeling of apprehension.

What is an operational definition?

The exact way a concept is measured or manipulated in a study, such as the score on a named anxiety instrument at discharge.

Why do operational definitions matter?

They make the study's procedures and outcome measurements specific, interpretable, and potentially reproducible.

What is a primary source?

An original report written by the researchers who conducted the study, such as the report of their clinical trial.

What is a secondary source?

A source that summarizes, interprets, or synthesizes original studies, such as a textbook or systematic review.

Is a systematic review primary or secondary evidence?

Secondary: it synthesizes original studies. It may nevertheless provide strong evidence for a clinical question.

Does peer review guarantee that a study is correct?

No. Peer review provides expert scrutiny but does not eliminate errors, bias, or limitations.

What is usually found in a research article's abstract?

A brief summary of the research question, methods, key results, and conclusions. Read the full study for appraisal.

What is usually found in the introduction and literature review?

The problem, its significance, prior knowledge, the gap in knowledge, and often the study purpose, question, or hypothesis.

What is included in a research article's methods section?

Design; setting; population and eligibility; recruitment and sample; assignment; intervention and comparison; instruments; data collection; ethical protections; and analysis plan.

Where would you look to learn who was eligible and how data were collected?

The methods section.

What is included in a research article's results section?

The actual sample and findings, including descriptive and inferential statistics in quantitative work or themes in qualitative work.

What is included in a research article's discussion?

Interpretation of findings, comparison with prior research, limitations, implications, and conclusions. Sections can be combined or named differently.

What is quantitative research?

Research using structured procedures and numerical measurement to describe variables, examine relationships, or test effects.

What are the main features of a true experimental design?

Researcher manipulation of an independent variable, a control or comparison group, and random assignment of participants to groups.

What is a randomized controlled trial (RCT)?

An experiment in which participants are randomly assigned to intervention and comparison conditions to evaluate outcomes.

What does random assignment accomplish in an RCT?

It helps balance known and unknown confounders between groups on average, although it cannot guarantee perfectly equal groups.

Is random sampling required for a true experiment?

No. Participants can be recruited by convenience and then randomly assigned to groups. Sampling and assignment are different.

What is quasi-experimental research?

Research that tests an intervention but lacks at least one defining feature of a true experiment, commonly random assignment or a control group.

A hospital introduces an intervention on one existing unit and compares it with another without random assignment. What design?

Quasi-experimental: the researcher introduces an intervention, but assignment to the existing units is not random.

What is a descriptive research design?

A design that describes characteristics, frequency, or distribution of variables without manipulating an intervention.

A researcher reports the percentage of nurses experiencing burnout. What type of study?

Descriptive research.

What is correlational research?

Nonexperimental research that examines whether measured variables are associated without manipulating them.

Does correlation prove causation?

No. Confounding, reverse causation, or other explanations can produce an association.

What is a cross-sectional study?

An observational study measuring variables at one point in time. It can describe prevalence but may not establish temporal order.

What is a cohort study?

An observational study that groups participants by exposure and assesses subsequent outcomes.

What is a case-control study?

An observational study that starts with outcome status and examines previous exposures.

What is blinding in research?

Masking group assignment from participants, clinicians, or assessors when feasible to reduce certain biases. It is distinct from random assignment.

What is the difference between random sampling and random assignment?

Random sampling determines who is selected from a population; random assignment determines which group enrolled participants enter.

What is the target population?

The entire group meeting relevant criteria to which researchers intend their findings to apply.

What is the accessible population?

The part of the target population that researchers can reasonably reach.

What is a sample?

The subset of a population selected or enrolled in a study.

What is an element in sampling?

An individual unit of the population or sample, often a person.

What is a representative sample?

A sample that resembles the relevant population on characteristics important to the study and its applicability.

Why does representativeness matter?

It supports a reasoned judgment about whether findings may generalize to the relevant population.

What are inclusion criteria?

Characteristics that define who is eligible to participate.

What are exclusion criteria?

Prespecified characteristics that rule out otherwise eligible individuals, for example for safety or design reasons.

How can narrow eligibility criteria affect a study?

They may improve control and interpretability but can limit applicability to a broader population.

What is probability sampling?

A sampling approach in which eligible population members have known, nonzero probabilities of selection. Implementation and nonresponse still affect representativeness.

What is simple random sampling?

Selection from the eligible sampling frame so each member has an equal chance, such as randomly drawing names from a roster.

What is systematic sampling?

Selecting every kth member from a list after a random start. A repeating pattern in the list can introduce bias.

What is stratified random sampling?

Dividing the population into relevant subgroups or strata and randomly sampling within each stratum.

What is nonprobability sampling?

Selection without a known random probability for every eligible population member; some members may not have a chance to be selected.

What is convenience sampling?

Selecting participants who are easiest to reach or available, such as the first 50 eligible patients on one shift.

What is quota sampling?

Setting desired numbers for subgroups and recruiting participants nonrandomly until those subgroup counts are filled.

How does quota sampling differ from stratified random sampling?

Both consider subgroups, but stratified random sampling randomly selects within strata; quota sampling does not require random selection within quotas.

What is purposive sampling?

Deliberately selecting people with relevant experience, knowledge, or characteristics; common in qualitative research.

What is snowball or network sampling?

Existing participants refer other potential participants. It can reach hard-to-find groups but social networks may produce a similar, biased sample.

What is theoretical sampling?

In grounded theory, selecting additional people or data based on emerging concepts to develop and refine the theory.

A researcher divides the roster by unit and draws names randomly within each unit. What sampling method?

Stratified random sampling.

A researcher recruits the first 50 available patients. What sampling method?

Convenience sampling, a nonprobability method.

What is sampling error?

The difference between a sample estimate and the population value due to chance selection of the sample.

What is sampling bias?

Systematic overrepresentation or underrepresentation of parts of the population, making the sample unrepresentative on important variables.

Does a larger sample automatically eliminate sampling bias?

No. Increasing sample size can reduce random sampling error but cannot automatically correct systematic selection bias.

What is effect size?

The magnitude of a difference or relationship. It is distinct from sample size and the p-value.

What is statistical power?

The probability of rejecting a false null hypothesis for a specified true effect; in other words, the ability to detect that effect.

What is a common planning target for statistical power in the lecture?

0.80, or 80%, although the appropriate target depends on the study.