1. Quantitative Research Designs

2. Research Design An overall plan for a study Causes Relationships
Historical data
Design must be appropriate to test research hypotheses or answer the research question (s)

3. Exploratory, Descriptive, and Explanatory studies
Exploratory studies:
- Little is known about phenomena
- Flexible approach rather than structured approach is
needed
- Examining qualitative data along with quantitative ones
- Hypotheses were not appropriate
- Data may be grouped, categorized, and generalized to
other populations

4. Exploratory, Descriptive, and Explanatory studies
Descriptive studies:
- To describe a phenomena or relationship
between variables
- Differ in amount of information gathered or
available about the problem under study in
comparison to exploratory
- Enough information may be available in literature

5. Exploratory, Descriptive, and Explanatory studies
- Search on causal explanations
- Much rigorous than exploratory or
descriptive
- Usually experimental
- Enough knowledge exists

6. Examples
The purpose of the study is to test an intervention to reduce chemotherapy-induced side effects—specifically, to compare the effectiveness of patient-controlled and nurse-administered antiemetic therapy for controlling nausea and vomiting in patients on chemotherapy.

7. Examples
The purpose of this study is to investigate the effects of nursing student-faculty interaction outside the classroom on students’ semester college grade point average.

8. Examples
The Relationship between Purpose in Life, Self-Acceptance and Perceived Stress among Jordanian Menopausal Women

9. Examples
The aim of this cross-sectional study is to evaluate student nurses' understanding of key nursing concepts at entry into the University Baccalaureate program in nursing.

10. Examples
To examine the differences among patients who developed wound haematoma post breast reduction surgery.

11. Examples
This study is designed to evaluate the effectiveness of using pressure ulcer (PU) risk assessment scales (RASs), namely the Braden scale, on patients’ outcomes in terms of PU incidence.
The study aimed to examine the effects of RASs (the Braden scale) compared to the effects of PU training and nurses’ clinical judgement on patients’ outcomes in terms of PU incidence.

12. Experimental Non-experimental
Research Designs
Experimental
Non-experimental

13. Experimental Research
True experimental (Manipulation, Randomization and Control)
Quasi-experimental
Pre-experimental

14. Experimental Research
Manipulation (Treatment or Intervention) :
Independent variable (s) controlled by the researcher
Examples:
New pre operative education method
New drugs
New methods of measuring vital signs
Risk assessment scales
Elevated or increased quality indicators
Sterile technique

15. Experimental Research
Control:
Applying control over comparison group
Withholding treatment (ethical issue?)
Receiving normal treatment or regular care
Receive different treatment (placebo)
Example:
Baseline data showed similar weight, age, free of infections among 20 students who volunteered in a new antibiotic experiment. Controlled group may not receive the drug, receive placebo, or receive another kind of antibiotics.

16. Experimental Research
Randomization:
Random assignment of subjects to control or experimental groups ensures that each subject had the same chance of being placed in any of the groups.
Examples:
Computer selection of subjects
Every other admitted patient
Select every Kth. Numbered of well known subjects

17. Symbolic representation of experimental research
R= Random assignment of subjects
O= observation or measurement of dependent variable (s)
X= Treatment or intervention
Example
RO1 X O2 (Experimental group)
RO1 O2 (Comparison or control group)

18. Types of experimental research True experimental designs
Pretest-posttest control group design
The most frequently used experimental design
Pretest done for both groups
Random assignment of subjects
Experimental group receive treatment while control receive routine, different, or no treatment.
Posttest done of both groups
Control internal validity threats
Generalized to situations in which a pretest would be administered before treatment
Disadvantages included external validity threats of reactive pretest.
RO1 X O2 (Experimental group) RO1 O2 (Comparison or control group) Example ETT suctioning and Oxygen saturation

19. Types of experimental research True experimental designs
Posttest only control group design
R X O1 (Experimental group)
R O1 (Comparison or control group)
Larger sample size will increase the effectiveness of random assignment
Example:
Improving wound healing rate using new modality (e.g. Mebo cream)

20. Types of experimental research True experimental designs
Solomon Four Group Design
2 groups pretested RO1 X O2 (Experimental group 1)
2 groups experimented RO1 O2 (Comparison or control group 1)
R X O2 (Experimental group 2)
R O2 (Comparison or control group 2)
All groups postested
It minimizes internal and external validity threats
Requires large sample
Statistical analysis is complicated

21. Types of experimental research Quasi-Experimental Designs
Researcher is not able to either conform comparison groups (control) or randomly assign subjects to groups
Naturally occurring groups in real world

22. Types of experimental research Quasi-Experimental Designs
Nonequivalent Control group Design
O1 X O2 (Experimental group)
O1 O2 (Comparison or control group)
No randomization
Similar Pre test post test design
History, testing, maturation, instrumentation change and selection bias may represent internal validity threats
If the groups were similar, more confidence could be placed in a cause-effect relationship between variables.
Example: The impact of using RAS on PU incidence among hospitalized patients

23. Types of experimental research Quasi-Experimental Designs
Time series Design
O1 O2 O3 X O4 O5 O6
Periodically observe or measure the subjects
Example : 3 weeks assessment of LBP before treatment (exercise, drug, or surgery)
Repeated measures help to strengthen validity of the design
The greatest threats to validity are history and testing

24. Pre-Experimental Designs

25. Types of experimental research Pre-Experimental Designs
One-shot Case study
A single group is exposed to an experimental treatment and observed after the treatment. XO
Example: observe a group of diabetic clients received diabetic education course
No comparisons made
No control over internal threats such as history, maturation, and selection bias.

26. Types of experimental research Pre-Experimental Designs
One-Group Pretest-Posttest Design
O1XO2
Example: A group of clients received a pretest of their knowledge concerning diabetes and then received educational course and then post tested.
Prominent internal threats such as maturation, history, testing and instrumentation.

27. Non-Experimental Designs

28. Non-Experimental Designs
Survey studies:
self report data are collected from samples to describe population on some variable (s).
Control applied through sampling technique and sample size (generalization)
Example : National polls
Applied in most social studies
In nursing, used to gather data on clients’ health needs, perceptions, or sleep patterns.
May be conducted by phone, mail or personal contact
Surveyors used commonly questionnaires or interviews
May be cross sectional or longitudinal
Advantages: accurate information through short period of time and small sample, minimal costs, large amount of information
Disadvantages included unreliable information and social responses

29. Non-Experimental Designs
Correlational studies
The researcher examines the strength of relationships between variables (Pearson r or spearman rho = -1 to 1)
It provides strength of relationship along with direction and magnitude.
Cannot conclude cause –effect relationship

30. Non-Experimental Designs
Comparative studies
Examines the differences between intact groups on some dependent variable (s)
Researcher cannot manipulate the independent variable (s)
Independents may represent inherent characteristics (variables) such as age, personality type, educational level, or medical condition.
Used in ethical conditions (child abuse cannot be manipulated)

31. Non-Experimental Designs
Comparative studies
PROSPECTIVE TYPE
Presumed cause (independent variable) at present time and then subjects followed in the future to observe presumed effect (dependent variable)
Example:
- Heamatoma among breast reduction Jordanian women
- PU among ICU patients
- High cholesterol levels and incidence of CAD.
* May be experimental????
* costs???
* dropout (attrition)??

32. Non-Experimental Designs
Comparative studies
RETROSPECTIVE STUDIES
“ Ex post facto studies”
Post the fact
Dependent identified in the present and independent followed in the past
Example:
- Lung cancer and smoking
- wound healing and different modalities used
- CAD risk factors
- H1N1
- Client’s health alterations (NCI’S)
- cost, experimentation, attrition????

33. Non-Experimental Designs
Methodological studies
- Examine reliability and validity of research instruments
(tools)
- develop, test, and evaluate research instruments and methods
- availability of the tools rather than appropriateness!!

34. Non-Experimental Designs
Secondary Analysis Studies
Data analysis of previously conducted study

35. Research designs according to settings

36. Laboratory
Simulation study
Field study

37. Validity of different designs (experimental)

38. Validity of research designs
Extraneous, contaminating, confounding and intervening variables
Internal validity: concerned the relationship between dependent and independent variables (cause-effect)
External Validity: concerned generalizability of results

39. Internal validity threats
Selection bias
History
Maturation
Testing
Instrumentation change
Mortality
Subjects are not randomly assigned to experimental and control groups
An event may influence the dependent variable
People may become older, taller, or sleepier or get weight gain
Subjects have baseline knowledge through pretesting (remember)
Different instruments used in pre and post testing
Attrition rate or dropout

40. External validity threats
Hawthorne effects
Experimenter effects
Reactive effects through pre test (measurement effect)
Aware participants about observation (double blinding)
Researcher characteristics or behaviors influence subjects behavior
Reactive effects of the pre test