Nurs 413 Ch.6 & 7

An appropriate research design will reflect
an integration of the theoretical and empirical literature that was presented in the review of the literature section of the study
Quantitative designs used to examine relationship among variables are categorized as:
experimental or nonexperimental
Experimental designs are used for
the purpose of examining causality
Nonexperimental designs can be used for
the purposes of describing a phenomenon in detail, explaining relationships and differences among variables, and predicting relationships and differences among variables
The major difference between nonexperimental and experimental designs is
the role of the researcher
In experimental designs, researchers
actively manipulate the independent variable (causal variable) to determine its effect on the dependent variable
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In nonexperimental designs, researchers
are observers noting the occurrence of the variables of interest and trying to determine relationships and differences.
the relationship between a cause and its effect
When outcomes have many causes, its called
Elements to consider when appraising quantitative designs
What type of quantitative design is being used?
Can causality be inferred?
Did researchers use the highest level of design possible to answer the research questions?
What strategies did the researcher use to control for the effects of extraneous variables?
What threats to internal and external validity might be present, and were any strategies used to reduce them?
Were there any ethical concerns about the design?
Likelihood or chance that an event will occur in a situation
ability to manipulate, regulate, or statistically adjust for factors that can affect the dependent variable
the ability of researchers to control the independent variable
Extraneous variable
factors that interfere with the relationship between the IV and DV
In health-related experimental designs, the control group of subject usually receives:
the standard of care, but does not get the intervention
when extraneous variables influence the relationship between the independent and dependent variables
the selection, assignment, or arrangement of elements by chance
Random sampling
technique for selecting elements whereby each has the same chance of being selected
Ransom assignment
subjects have an equal chance of being in either the treatment or the control group
Between-group design
study design where two groups of subjects can be compared
Within-groups design
comparisons are made about the same subjects at two or more points in time or on two or more measures
Study validity
ability to accept results as logical, reasonable, and justifiable based on the evidence presented.
Evaluating the quality of quantitative evidence requires the nurse to
identify potential threats to validity, evaluate the seriousness of those threats, and determine if results are valid for application to patient care
are forces that can change the results of the study
When designing a study, which of the following should the researcher consider: (select all that appyl)
a. research question
b. review of the literature
c. theoretical framework
d. study purpose
a. research question
b. review of the literature
c. theoretical framework
d. study purpose
Which of the following is not a purpose of nonexperimental designs:
a. describe phenomenon
b. explain relationships
c. predict relationships
d. examine causality
d. examine causality
The researcher’s ability to manipulate or regulate extraneous variables is known as:
a. control
b. manipulation
c. bias
d. probability
a. control
When a researcher assign subjects to groups by tossing a coin, the researcher is using:
a. random selection
b. random assignment
c. bias
d. within-groups design
b. random assignment
Internal validity
the degree to which one can conclude that the IV produced changes in the DV
Common threats to internal validity include:
selection bias
statistical conclusion validity
Selection bias
a threat to internal validity when the change in the DV is a result of to characteristics of the subjects before they entered the study
Selection bias con be minimized somewhat by
the use of random assignment to groups
a threat to internal validity when the dependent variable is influenced by an event that occurred during the study
The threat of history can be decreased by
having a control group that is exposed to the “event” but does not receive the intervention
a threat to internal validity when subjects change by growing or maturing
What can help limit maturation threat to internal validity?
control group
a threat to internal validity when a pretest influences the way subjects respond on a posttest
Repeated testing can cause _________ with the test itself and ______ may reflect subjects’ abilities to remember how the questions were ________ previously rather than reflecting __________ and _________.
current knowledge
threat to internal validity when there are inconsistencies in data collection
To control for the threat of instrumentation, researchers need to ensure
comprehensive training of all data collectors
a threat to internal validity when there is a loss of subjects before the study is completed
Attrition rate
dropout rate
If the attrition rate is high the author of the article should
provide an analysis and explanation for the dropout rate
Statistical conclusion validity
the degree that the results of the statistical analysis reflect the true relationship between the IV and DV
Type II error
when researchers inaccurately conclude that there is no relationship between the IV and DV
Researches can control for low reliability of the measure by
using well-established and well-designed instruments
External validity
the degree to which the results of the study can be generalized
Construct validity
a threat to external validity when the instrument does not accurately measure the theoretical concepts
the influence of participating in a study on the responses of subjects
Hawthorne effect
subjects’ behaviors affected by personal values or desires to please the experimenter
Double-bind experimental designs
studies where subjects and researchers are unaware if they’re experimental interventions or standard of care
Effects of selection
threat to external validity when the samples does not represent the population
Interaction of treatment with selection of subjects
a threat to external validity where the IV might not affect individuals the same way
Interaction of treatment and setting
a threat to external validity when an intervention conducted in one setting cannot be generalized using the same intervention
The degree to which the results of studies can be generalized to other individuals, settings, or time is:
a. external validity
b. construct validity
c. internal validity
d. statistical conclusion validity
a. external validity
During a study examining nurses’ job satisfaction, the union decides to hold a strike. This is what type of threat to internal validity:
a. selection bias
b. mortality
c. history
d. testing
c. history
A researcher plans to observe children in a kindergarten class. Students have always been told to be on their best behavior when guests are present in the classroom. What is the greatest threat to external validity:
a. construct validity
b. Hawthorne effect
c. selection
d. interaction of treatment setting
b. Hawthorne effect
Interaction of treatment and history
a threat to external validity when historical events affect the intervention
Retrospective design
research design when researchers look back in time to determine possible causative factors
ex post factor
retrospective research design
Case control
retrospective study where research begins with people who already had the disease
Retrospective designs are often used
in epidemiological studies
Because retrospective designs are not experimental, a disadvantage is
that researchers cannot say definitively that to IV caused the DV; instead they can conclude that there is an increased likelihood or probability that the IV caused the DV
nonexperimental designs used to gather data from a group of subjects at only one point in time
Cohort comparison
more than one group is studied at the same time so that conclusion about a variable over time can be drawn without spending as much time
Advantages of cross-sectional designs
easier to manage and are more economical; data is collected only one time so the threats of mortality, maturation, and testing are minimized
Limitation of cross-sectional design
difficult for researchers to make claims about cause and effect
Longitudinal designs
designs used to gather data about subjects at more than one point in time
Prospective designs
studies over time with presumed causes that follow subjects to determine if the hypothesized effects actually occur
Panel design
longitudinal design where the same subjects provide data from different samples across time
a type of longitudinal design to gather data different samples across time
a longitudinal design used to follow subjects into the future
Nonexperimental studies differ from panel studies in that
the samples are not drawn from the general population, but instead samples are selected because they have a specific characteristic or condition that researchers are interested in studying
experimental design using two or more treatments; subjects receive treatments in random order
One problem with crossover studies
carryover effect, where even though the subjects are asked to stop performing the 1st intervention, the may continue to use it during the 2nd intervention
The term longitudinal is reserved for
studies in which data are gathered over extended period of time rather than in just a few hours or days
Advantage of longitudinal studies
can be used to test cause and effect
Disadvantage of longitudinal studies
costs in following subjects over an extended period of time
In retrospective designs, also known as ex post facto designs, the researchers manipulates the IV. True or false
Cohort comparison studies can save time because more than one group of subjects is studied. True or False
The threat of mortality is greater in cross-sectional designs than in longitudinal designs. True of False
Any study that involves collecting data at multiple points in time is a longitudinal study. True or False
To be considered a true experimental design, 3 features must be included:
randomization, control, and manipulation
experimental design
design involving random assignment to group and manipulation of the IV
Randomization happens in 2 ways
randomly select subject from the target population
randomly assign subjects to groups
Control group is one strategy to
control for extraneous variables
Researchers must be able to ________ the IV for a design to be considered experimental
RCT (randomized controlled trial)
the study is clinical in nature rather than a specific type of design
RCTs are characterized by the following
1. they involve a large # of subjects, often from diverse geographical areas
2. there are strict guidelines for including subject in a study
3. subjects are randomly assigned to interventions and control groups
4. groups must be comparable on key characteristics at baseline
5. the intervention is consistently implemented to all subjects in the experimental group following a very rigidly defined protocol for implementation
6. all subjects in both groups are measured on the DV using the same method of measurement at the same points in time
6 types of true experimental designs
1. two-group pretest-posttest
2. two group, posttest only
3. Solomon four group
4. multiple experimental groups
5. factorial
6. crossover designs
Two-group pretest-posttest designs
subjects are randomly assigned to the experimental or control group, and measured before and after the intervention
What is considered to be the classic experimental design?
Two group pretest-posttest
Two group posttest only design
an experimental design when subjects are randomly assigned to an experimental or control group and measured after the intervention
Solomon four group design
an experimental design with four groups, some receive the intervention, other serve as control; some are measured before and after, others only measured after the intervention
Potential disadvantage of the two group pretest-posttest design
repeated testing threats
Disadvantage of the two group posttest only design
susceptible to the threats of selection bias
Multiple experimental groups design
experimental design using two or more experimental groups with one control group
Why is the Soloman four group a superior design than the two group pretest posttest?
Reduction of testing threat; also superior to two group posttest only because it minimizes selection bias
Factorial design
experimental design allowing researchers to manipulate more than one intervention
Advantages of multiple group design
allows researchers to compare the effect of different interventions on the DV
Disadvantage of multiple group design
a large # of subjects are needed to detect differences across multiple groups
All experiments must include a minimum of two groups of subjects. True or False
The Solomon Four group design is more effective at controlling for the threat of testing than is the two group pretest posttest design. True or False
In a factorial design, only one group of subjects is required because they act as their own control. True or false
Patients who are not in the intervention group must receive the standard of care. True or False
Crossover design
experimental design using two or more treatments and subjects receive both treatments in a random order
Who is the control group in a crossover design?
the subjects serve as their own control group
Quasi-experimental designs
research designs involving the manipulation of the IV but lacking either two groups or a control group
3 quasi-experimental designs
1. nonequivalent control group pretest-posttest
2. time series designs
3. preexperimental designs
Nonequivalent control group pretest posttest design
a quasi experimental design where two groups are measured before and after an intervention
Time series design
a quasi-experimental design where one group is measured prior to administering the intervention and then multiple times after the intervention
One group posttest only design
a preexperimental design involving one group and a posttest with little control for extraneous variables
The difference between pre and quasi experimental designs is
that quasi, while lacking some elements of an experiment, use other strategies to control for extraneous variable
Nonequivalent groups posttest only design
a preexperimental design involving two groups measured after an intervention with little control for extraneous variables
a posttest only design that involves manipulation of the IV but lacks control for extraneous variables
Quasi experimental designs include which on the following essential components: (select all that apply)
1. randomization, control group, and manipulation of IV
2. randomization, and control group
3. comparison group and manipulation of IV
4. randomization and manipulation of IV
3. comparison group and manipulation of IV
4. randomization and manipulation of IV
Experimental designs have control groups. Quasi experimental designs have which of the following:
a. control groups
b. comparison groups
c. extraneous groups
d. peer groups
b. comparison groups
Rank the evidence generated from the following designs from lowest to highest:
a. experimental designs
b. nonequivalent control group pretest posttest
c. one group posttest only
d. nonequivalent groups posttest only
c, d, b, a
nonexperimental design
a research design that lacks manipulation of the IV and random assignment
Nonexperimental designs are important when
there is little information known about a particular phenomenon, when it would be unethical to manipulate the IV, or when it is not practical to conduct an experiment.
Nonexperimental designs are used for the purpose of:
1. describing a phenomenon in detail
2. explaining relationships and differences among variables
3. predicting the relationships and differences among variables
Two general ways the nonexperimental designs can be categorized
descriptive and correlational
Descriptive design
provide a picture of a situation as it is naturally happening without manipulation of any of the variables
Exploratory design
nonexperimental design used when little is known about a phenomenon
Comparative design
descriptive design that compares 2 or more groups or variables
Survey design
a descriptive design involving data obtained through subjects’ self report
Correlational design
nonexperimental design used to study relationship between two or more variables
Can causal statement be made with correlational designs?
No because they do not involve manipulation of IV
when change in one variable is associated with change in another variable
3 types of correlational designs
predictive correlational
Descriptive correlational design
used to explain the relationship among the variables or groups using a nondirectional hypothesis
Predictive correlational design
when researchers hypothesize which variables are predictors or outcomes
Two aims of predictive designs
1. researchers attempt to determine the amount of variance in an outcome variable that can be explained by multiple predictive variables
2. determining group membership
correlational design to test a hypothesized theoretical model
True causality can only be established with
an experimental design
In nonexperimental designs, researchers manipulate the IV to determine cause and effect. True or False
Nonexperimental design can be used to develop and test theories
The purposes of nonexperimental designs are to describe, explain, and predict relationships.
Descriptive data are usually cross-sectional and can be controlled through surveys and questionnaires
Researchers use correlations to determine if there are differences between two groups
Translational research
research for the purpose of linking research findings to the point of care
What agency is committed to the support of translational research?
The Agency for Healthcare Research and Quality (AHRQ)
Community-based participatory action research (CBPAR)
active involvement of community members throughout the research process
Critical principles for CBPAR include
engaging in collaborative, equitable partnerships, building on resources and using dynamic processes where ideas flow between researchers and community members
Health services research
research involving phenomena related to the delivery of health care

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