NURS 360 Exam 2

key questions for quantitative research design

Will there be an intervention?
What types of comparisons will be made?
How will confounding variables be controlled?
Will blinding be used?
How often will data be collected?
When will "effects" be measured, relative to potential causes?

causality

Many (if not most) quantitative research questions are about causes and effects.
Research questions that seek to illuminate causal relationships need to be addressed with appropriate designs.

counterfactual

is what would have happened to the same people exposed to a "cause" if they simultaneously were not exposed to the cause.

effect

represents the difference between what actually did happen when exposed to the cause and what would happen with the counterfactual condition.

three criteria for making causal inferences

temporal
relationship
confounder

temporal

The cause must precede the effect in time.

relationship

There must be a demonstrated association between the cause and the effect.

confounder

The relationship between the presumed cause and effect cannot be explained by a third variable or confounder; another factor related to both the presumed cause and effect cannot be the "real" cause.

biological plausibility

The causal relationship should be consistent with evidence from basic physiologic studies.

what type of design offers the strongest evidence?

Experimental designs (RCTs) offer the strongest evidence of whether a cause (an intervention) results in an effect (a desired outcome).
That's why they are high on evidence hierarchies for questions about causes and effects

within/between group comparison design considerations

CAN USE EITHER OR BOTH IN A STUDY
WITHIN-GROUPS
COMPARISONS ABOUT MEASUREMENTS MADE WITH SAME SUBJECTS AT DIFFERENT POINTS IN TIME
BETWEEN-GROUPS
COMPARISONS MADE WITH MORE THAN ONE GROUP OF SUBJECTS AT ONE OR MORE POINTS IN TIME

intervention

The researcher does something to some subjects—introduces an intervention (or treatment).
Pre- and posttests

control

The researcher introduces controls, including the use of a control and experimental groups.

randomization

The experimenter assigns participants to a control or experimental condition on a random basis.

what is the purpose of randomization?

The purpose is to make the groups equal with regard to all other factors except receipt of the intervention.

design symbols schema: R

randomization

design symbols schema: O

Measurement at a point in time
(Observation, data collection)

design symbols schema: X

Intervention or Treatment
Can sometimes be listed at T

posttest-only (or after-only) design

Outcome data collected only after the intervention
Symbolic representation
R X O
R O
R = Randomization; X = Receipt of intervention; O = Observation/measurement of dependent variable

pretest-posttest (before-after) design

Outcome data collected both at baseline and after the intervention
Symbolic representation
R O X O
R O O

crossover design

Subjects are exposed to 2+ conditions in random order.
Subjects serve as their own control.
Symbolic representation
R O XA O XB O
R O XB O XA O

experimental condition

Must be designed with sufficient intensity and duration that effects might reasonably be expected
Researchers describe the intervention in formal protocols that stipulate exactly what the treatment is.
Attention must be paid to intervention fidelity (or treatment fidelity), that is, whether the treatment as planned was actually delivered and received.

control group conditions (counterfactuals)

No intervention is used; control group gets no treatment at all.
"Usual care" or standard or normal procedures is used to treat patients.
An alternative intervention is used (e.g., auditory vs. visual stimulation).
A placebo or pseudointervention, presumed to have no therapeutic value, is used.
Attention control condition and delayed treatment (wait-listed)

attention control

extra attention but not the active ingredient of the intervention

delayed treatment

("wait-listed controls")—the intervention is given at a later date.
Symbolic representation
R O X O O
R O O X O

advantages of experiments

most powerful for detecting cause and effect relationships

disadvantages of experiements

often not feasible or ethical, Hawthorne effect (knowledge of being in a study may cause people to change their behavior), often expensive

quasi experiments

Involve an intervention but lack either randomization or control group
Two main categories of quasi-experimental designs
Nonequivalent control group designs
Those getting the intervention are compared with a nonrandomized comparison group.
Within-subjects designs
One group is studied before and after the intervention.

nonequivalent control group pretest-posttest design

If pre intervention data are gathered, then the comparability of the experimental and comparison groups at the start of the study can be examined.
Nonequivalent control group pretest-posttest design
Symbolic representation
O1 X O2
O1 O2

nonequivalent control group posttest only

Without pre intervention data, it is risky to assume the groups were similar at the outset.
Nonequivalent control group posttest only is much weaker.
Symbolic representation
X O1
O1

one-group pretest-posttest designs

typically yield extremely weak evidence of causal relationships.
Symbolic representation
O1 X O2

time-series designs

gather preintervention and postintervention data over a longer period.
Symbolic representation
O1 O2 O3 O4 X O5 O6 O7 O8

advantages and disadvantages of quasi-experiments

May be easier and more practical than true experiments but
They make it more difficult to infer causality.
Usually there are several alternative rival hypotheses for results.

nonexperimental studies

If researchers do not intervene by controlling independent variable, the study is nonexperimental (observational).
Not all independent variables ("causes") of interest to nurse researchers can be experimentally manipulated.
For example, gender cannot ever be manipulated.
Smoking cannot ethically be manipulated.

correlational designs

Correlational designs
Cause-probing questions (e.g., Prognosis or Etiology/harm questions) for which manipulation is not possible are typically addressed with a correlational design.
Correlational studies are weaker than RCTs for cause-probing questions, but different designs offer varying degrees of supportive evidence.

correlation

an association between variables and can be detected through statistical analysis.

prospective correlational design

a potential cause in the present (e.g., experiencing vs. not experiencing a miscarriage) is linked to a hypothesized later outcome (e.g., depression 6 months later).
This is called a cohort study by medical researchers.
Prospective designs are stronger than retrospective designs in supporting causal inferences—but neither is as strong as experimental designs.

retrospective correlational design

an outcome in the present (e.g., depression) is linked to a hypothesized cause occurring in the past (e.g., having had a miscarriage).

case-control design

in which "cases" (e.g., those with lung cancer) are compared to "controls" (e.g., those without lung cancer) on prior potential causes (e.g., smoking habits).

descriptive research

Not all research is cause probing.
The purpose of descriptive studies is to observe, describe, and document aspects of a situation.
Some research is descriptive (e.g., ascertaining the prevalence of a health problem).
Other research is descriptive correlational

descriptive correlational

the purpose is to describe whether variables are related, without ascribing a cause-and-effect connection.

advantage of nonexperimetnal research

efficient way to collect large amounts of data when intervention and/or randomization is not possible

disadvantages of nonexperimental research

does not yield persuasive evidence for causal inferences
This is not a problem when the aim is description, but correlational studies are often undertaken to discover causes.

cross-sectional design

Data are collected at a single point in time.

longitudinal design

Data are collected two or more times over an extended period.
Follow-up studies
Longitudinal designs are better at showing patterns of change and at clarifying whether a cause occurred before an effect (outcome).
A challenge in longitudinal studies is attrition or the loss of participants over time.

controlling external factors

Achieving constancy of conditions
Control over environment, setting, time
Control over intervention via a formal protocol: intervention fidelity

controlling participant factors

Randomization
Subjects as own controls (crossover design)
Homogeneity (restricting sample)
Matching
Statistical control (e.g., analysis of covariance)

statistical conclusion validity

the ability to detect true relationships statistically

internal validity

the extent to which it can be inferred that the independent variable caused or influenced the dependent variable

external validity

the generalizability of the observed relationships across samples, settings, or time

construct validity

the degree to which key constructs are adequately captured in the study
the degree to which evidence about a measure's scores in relation to other variables supports the inference that the construct has been well represented

threats to statistical conclusion validity

Low statistical power (e.g., sample too small)
Weakly defined "cause"—independent variable not powerful
Unreliable implementation of a treatment—low intervention fidelity

threats to internal validity

Temporal ambiguity
Selection threat—biases arising from preexisting differences between groups being compared
This is the single biggest threat to studies that do not use an experimental design.
History threat—other events co-occurring with causal factor that could also affect outcomes
Maturation threat—processes that result simply from the passage of time
Mortality/attrition threat—differential loss of participants from different groups
Typically a threat in experimental studies

selection threat

biases arising from preexisting differences between groups being compared
This is the single biggest threat to studies that do not use an experimental design.

history threat

other events co-occurring with causal factor that could also affect outcomes

maturation threat

processes that result simply from the passage of time

mortality/attrition threat

differential loss of participants from different groups
Typically a threat in experimental studies

threat to internal validity: testing

Multiple testing might influence subjects response on subsequent testing
Threat Reduction
Post test only design
Control group tested same # times or prolong length of time between tests

threat to external validity

person, place, time
Inadequate sampling of study participants
Unfortunately, enhancing internal validity can sometimes have adverse effects on external validity.

threats to construct validity

Is the intervention a good representation of the underlying construct?
Is it the intervention or awareness of the intervention that resulted in benefits?
Does the dependent variable really measure the intended constructs?

Tell whether the following statement is True or False.
An experimental research design involves a nonrandomized controlled trial.

False
Rationale: A quasi-experimental research design involves a controlled trial without randomization.

Which characteristic is a key criterion for causality?
A) Cause occurring before the effect
B) Third variable involved with the cause and effect
C) No empirical relationship between the cause and effect
D) Single-source evidence about the relationship

A) Cause occurring before the effect
Rationale: Three key criteria for causality include the following:
The cause must precede the effect in time.
There must be a demonstrated empirical relationship between the cause and effect.
The relationship cannot be explained by a third variable.
An additional criterion is that evidence of the relationship should come from multiple sources.

Tell whether the following statement is True or False.
A true experiment requires that the researcher manipulate the independent variable by administering an experimental treatment (or intervention) to some subjects while withholding it from others.

True
Rationale: In a true experiment, the researcher manipulates or does something, usually an intervention or treatment, to some subjects and not to others.

Which design is considered a quasi-experimental research design?
A) Pretest-posttest design
B) Posttest-only design
C) Crossover design
D) Within-subjects design

D) Within-subjects design
Rationale: Quasi-experimental research designs include nonequivalent control group and within-subjects designs. The other research designs are used for experimental research.

Tell whether the following statement is True or False.
Cross-sectional research designs are helpful in showing patterns of change.

False
Rationale: Longitudinal studies, in which data are collected two or more times over an extended period, are better at showing patterns of change than cross-sectional studies, which collect data at a single point in time.

sampling in qualitative research

Qualitative researchers are as concerned as quantitative researchers with the quality of their samples, but they use different considerations in selecting study participants.
Selection of sample members guided by desire for information-rich data sources
"Representativeness" not a key issue
Random selection not considered productive

convenience sampling

(volunteer) sampling; not preferred approach but economical
selecting the most conveniently available people as participants

purposive sampling

Researchers deliberately choose the cases that will best contribute to the study.
handpicking sample members

snowball sampling

(network sampling): Sample might be restricted to a small network of acquaintances.

theoretical sampling

involves decisions about where to find data to develop an emerging theory optimally
Preferred sampling method in grounded theory research
Involves selecting sample members who best facilitate and contribute to the development of the emerging theory

types of purposive sampling in qualitative research

Maximum variation sampling
Extreme/deviant case sampling
Typical case sampling
Criterion sampling
Confirming and disconfirming cases

sample size in qualitative research

No explicit, formal criteria
Sample size determined by informational needs
Decisions to stop sampling guided by data saturation
Data quality can affect sample size.

sampling in phenomenology

Relies on very small samples (often 15 or fewer)
Two principles guide sample selection
Participants must have experienced phenomenon of interest.
They must be able to articulate what it is like to have lived that experience.
May sample artistic or literary sources

sampling in grounded theory

Typically involves samples of 20 to 30 people
Selection of participants who can best contribute to emerging theory (usually theoretical sampling)

critically appraising qualitative sampling plans

Appropriateness
Adequacy
Transferability

data collection in qualitative studies

Data collection methods may change as study progresses.
In-depth interviews most common method
Observation also common

unstructured interviews

Conversational, totally flexible
Use of grand tour questions

semi-structured interview

Use of a topic guide

focus group interviews

Interviews in small groups (5 to 10 people)
Led by a moderator

diaries

Source in historical research
Provide intimate detail of everyday life

photo elicitation

Interview stimulated and guided by photographic images
Photovoice: asking participants to take photos themselves and interpret them

qualitative observational methods

Qualitative studies: unstructured observation in naturalistic settings
Includes participant observation

gathering qualitative self-report data

Researchers gather narrative self-report data to develop a construction of a phenomenon that is consistent with that of participants.
This goal requires researchers to overcome communication barriers and to enhance the flow of information.

gathering participant observation data

The physical setting
The participants
Activities
Frequency and duration
Process
Outcomes

recording observations

Logs (field diaries)
Field notes
Descriptive (observational) notes
Reflective notes
Researcher's personal experiences
Reflections
Progress in the fields

evaluations of unstructured observational methods

Excellent method for capturing many clinical phenomena and behaviors
Observers may lose objectivity in sampling, viewing, and interpreting observations.
Emotional involvement might become a concern.
Researchers in their member role may develop a myopic view on issues of importance to the group.
The success of participant observation depends on the observer's observational and interpersonal skills.

Tell whether the following statement is True or False.
Sampling in qualitative research is guided more by the desire for rich sources of information than by the need for random selection.

True
Rationale: Selection of sample members for qualitative research is guided by the desire for information-rich sources. The representativeness of the sample is not a key aspect, and random selection is not considered productive.

Tell whether the following statement is True or False.
A focus group typically involves at least 10 to 15 people.

False
Rationale: A focus group usually involves interviews with small groups, ranging in size from 5 to 10 people.

Tell whether the following statement is True or False.
In qualitative studies, observation is unstructured.

True
Rationale: Observation with a qualitative study is unstructured and occurs in naturalistic settings.

characteristics of qualitative research design

Is flexible, capable of adjusting to what is learned during data collection
Benefits from ongoing data analysis to guide subsequent strategies
Often involves triangulating various data sources
Tends to be holistic, aimed at understanding the whole
Requires researchers to become intensely involved and reflexive
Emergent: evolves as researchers make ongoing decisions about their data needs based on what they have already learned

ethnography

Describes and interprets a culture and cultural behavior
Culture is the way a group of people live—the patterns of activity and the symbolic structures (e.g., the values and norms) that give such activity significance.
Relies on extensive, labor-intensive fieldwork
Culture is inferred from the group's words, actions, and products of its members.
Assumption: Cultures guide the way people structure their experiences.
Macroethnography vs. focused ethnography
Seeks an emic perspective (insider's view) of the culture and to reveal tacit knowledge—information about the culture that is deeply embedded in the culture
Relies on wide range of data sources and three broad types of information: cultural behavior, cultural artifacts, and cultural speech
Participant observation is a particularly important source.
Product: an in-depth, holistic portrait of the culture under study

emic perspective

insider's view

phenomenology

Focuses on the description and interpretation of people's lived experience
Asks: What is the essence of a phenomenon as it is experienced by people, and what does it mean?
Acknowledges people's physical ties to their world: "being in the world"

descriptive phenomenology

Based on philosophy of Husserl and his question: "What do we know as persons?"
Describes human experience
Insists on the careful portrayal of ordinary conscious experience of everyday life—a depiction of "things" as people experience them
Hearing, seeing, believing, feeling, remembering, deciding, and evaluating
May involve maintaining a reflexive journal

phases of descriptive phenomenological study

bracketing, intuiting, analyzing, describing

bracketing

the process of identifying and holding in abeyance preconceived beliefs and opinions about the phenomenon under study

intuiting

occurs when researchers remain open to the meanings attributed to the phenomenon by those who have experienced it

analyzing

extracting significant statements, categorizing, and making sense of essential meanings

describing

defining the phenomenon

interpretive phenomenology

Based on philosophy of Heidegger; Heideggerian: hermeneutics as a basic characteristic of human existence
Gadamer: the hermeneutic circle
Emphasis on interpreting and understanding experience, not just describing it; bracketing does not occur.
Relies on in-depth interviews and supplementary data sources: texts, artistic expressions