A blue print to conduct a research study, which involves the description of research approach, study setting, sampling size, techniques, tools and methods of data collection and analysis the answer of research questions.
Factors affecting selection of research design
* Nature of the research problem: This is the most important factor, which helps the researcher to decide about the selection of a research design. Based on the nature of research problem or phenomenon, researchers decide whether it should be investigated through an experimental, quasi-experimental, or nonexperimental approach.
* Purpose of the study: Study may be conducted for the purpose of prediction, description, exploration, or correlation of the research variables. Therefore, the purpose of the research study helps the researcher to choose a suitable research design.
* Researcher’s knowledge and experience: Selection of research design is largely influenced by the researchers’ knowledge and experience, because they avoid using those designs wherein they lack confidence, relevant knowledge, or experience. Hence the awareness of and expertise in existing research designs are important factors pertaining to the researchers.
* Researcher’s interest and motivation: Interest and motivation levels help researchers decide about the particular research design(s). Motivated researchers always analyses most aspects of research design before selecting one or a combination.
* Research ethics and principles: The incorporation and application of ethical and legal principles in the research design are essential. This includes moral obligations such as respect for participants and their rights, informed consent, and protection from harm, including any adverse effects to educational progress, health, and well-being.
* Subjects/participants: The number and availability of study subjects may infuence the selection of research design. If only few subjects are involved, an in-depth qualitative research design study may be chosen method, but in case of a large sample, the researcher may opt for a quantitative research design.
* Resources: None of the researches can be conduct without resources such as money, equipment’s, facilities, and support from colleagues. However, some of the studies require more amounts of resources as compared to others. Therefore, the selection of a research design may be affected by the availability of resources for the research study.
* Time: Time is also a major deciding factor for the selection of research design. For example, a researcher needs more time to conduct longitudinal studies, while cross-sectional studies may be conducted in shorter time. Therefore, time is also a significant contributing factor in selection of a research design.
* Possible control on extraneous variables: An efficient design can maximize results, decrease errors, and control pre-existing or impaired conditions that may affect the outcome of the study. For example, a researcher wants to conduct a study through true-experimental design but because of inability to control selected extraneous variables, other similar design has to be opted for, such as quasi-
* Users of the study findings: A research design also involves various methods of data collection and data analysis. Therefore, while choosing a research design, researcher must that maximum advantage of the results can be obtained ensure that research design is as appropriate for the users of the study findings as possible,
Types of research design
1. Quantitative research design: Experimental, Non-experimental, Other research design
2. Qualitative research design: Phenomenological, Ethnographic, Grounded theory, Case studies, Historical and Action research
QUANTITATIVE RESEARCH DESIGN
A. EXPERIMENTAL RESEARCH DESIGNS
Experimentation is the most scientifically sophisticated research method. It is defined as ‘observation under controlled conditions’.
According to Riley, Experimental research design is a powerful design for testing hypotheses of causal relationship among variables. Ideally in the experimental design the investigator throws in a sharp relief of explanatory variables in which he is interested, controlling and manipulating the independent variable and observing its effect on the dependent variable and minimizing the effect of extraneous variables, which might confound his results.
1. TRUE EXPERIMENTAL DESIGNS
True experimental research designs are those where researchers have complete control over the extraneous variables and can predict confidently that the observed effect on the dependable variable is only due to the manipulation of the independent variable.
Types of true experimental research-
1. Post-test-only control design: Composed of two randomly assigned groups, i.e. experimental and control, but neither of which is pretested before the implementation of treatment on the experimental group. This design can be helpful in situations where it is not possible to pretest the subjects. For example, to study the effect of an educational intervention related to urinary incontinence on the subsequent help-seeking behaviour of older adults.
2. Pretest-post-test-only design: In this research design, subjects are randomly assigned to either the experimental or the control group. The effect of the dependent variable on both the groups is seen before the treatment (pretest).
3. Solomon four-group design: There are two experimental groups (experimental group 1 and experimental group 2) and two control groups (control group 1 and control group 2). Initially, the investigator randomly assigns subjects to the four groups. Out of the four groups, only experimental group i and control group 1 receives the pretest, followed by the treatment to the experimental group 1 and experimental group 2. Finally, all the four groups receive post-test, where the effects of the dependent variables of the study are observed and comparison is made of the four groups to assess the effect of independent variable (experimental treatment) on the dependent variable.
4. Factorial design: In factorial design, researcher manipulates two or more independent variables simultaneously to observe their effects on the dependent variables. This design is useful when there are more than two independent variables, called factors to be tested.
5. Randomized block design: When there are a large number of experimental comparison groups, the randomized block sign is used to bring homogeneity among selected different groups. This is simple method to reduce he variability among the treatment groups by a more homogeneous combination of the subjects through randomized block design.
6. Crossover design: In this design, subjects are exposed to more than one treatment, where subjects are randomly assigned to different orders of treatment. It is also known as ‘repeat measures design’. This design is more efficient in establishing the highest possible similarity among subjects exposed to different conditions, where groups compared obviously have equal distribution of characteristics. Though crossover design is considered as an extremely powerful research design, sometimes it is not effective because when subjects are exposed to two different conditions, their responses of the second condition may be influenced by their experience in the first condition.
Advantages of True Experimental Design
* Experimental research designs are considered the most powerful designs to establish the causal relationship between independent and dependent variables.
* Where the purpose of research is explanation, causal relationship may be established among the variables by experimentation, especially in studies involving physical objects, where the variables are more easily controlled than in human studies.
* In these studies, the controlled environment in which the study is conducted can yield a greater degree of purity in observation.
* Conditions not found in a natural setting can be created in an experimental setting, where the independent variable is manipulated by investigator.
* In the experimental approach, we can often create conditions in a short period of time that may take years to occur naturally. For example, in genetic studies we can breed strains in very small time, which would take a long time in nature to occur.
* When the experiment is conducted in a laboratory, experimental unit, or other specialized research setting, it is removed from the pressure and problems of real-life situations and the researcher can pursue his or her studies in a more leisurely, careful, and concentrated way.
2. QUASI-EXPERIMENTAL RESEARCH DESIGN
Quasi-experimental research design involves the manipulation of independent variable to observe the effect on dependent variable, but it lacks at least one of the two characteristics of the true experimental design: randomization or a control group.
Types of Quasi-Experimental Designs-
Quasi-experimental designs may be of several types, but two most frequently used designs are discussed
A. Nonrandomized control group design: It is also known as the ‘nonequivalent control group design’. This design is identical to the pretest-posttest control group design, except there is no random assignment of subjects in experimental and control groups. In this design, experimental and control groups are selected without randomization, and dependent variables are observed in experimental as well as control groups before the intervention.
Exp. Group: Pretest, Treatment, Post-test
Control group: Pretest, Post-test
A. Time-series design:
* This design is useful when the experimenter wants to measure the effects of a treatment over a long period of time.
* The experimenter would continue to administer the treatment and measure the effects a number of times during the course of the experiment.
* Generally it is a single-subject research, in which the researcher carries out an experiment on an individual or on a small number of individuals, by alternating between administering and then withdrawing the treatment to determine the effectiveness of the intervention.
Advantages of Quasi-Experimental Design
* Quasi-experimental designs are more frequently used because they are more practical and feasible to conduct research studies in nursing, where in the absence of a large sample size, randomization and/or availability of control groups are not always possible.
* This design is more suitable for real-world natural setting than true experimental research designs.
* It allows researchers to evaluate the impact of quasi-independent variables under naturally occurring conditions.
* It may be able to establish causal relationship, wherein some of the hypotheses are practically answered through this design only.
3. PRE-EXPERIMENTAL RESEARCH DESIGN
This research design is considered very weak, because the researcher has very little control over the experiment.
Types of Pre-Experimental Research Design-
1. One-shot case design: In this research design, a single experimental group is exposed to a treatment and observations are made after the implementation of that treatment. There is no random assignment of subjects to the experimental group and no control group
2. One-group pretest-posttest design: It is the simplest type of pre-experimental design, where only the experimental group is selected as the study subjects. A pretest observation of the dependent variables is made before implementation of the treatment to the selected group, the treatment is administered and finally posttest observation for dependent variables.
Advantages
* Very simple and convenient to conduct these studies in natural settings, especially in nursing.
* Most suitable design for the beginners in the field of experimental research.
B. NON-EXPERIMENTAL RESEARCH DESIGNS
I- Descriptive design
* Univariant descriptive design
* Exploratory descriptive design
* Comparative descriptive design
II- Correlational/Ex-post facto design
* Prospective design
* Retrospective design
III- Developmental research design
*Cross-sectional design
* Longitudinal design
IV-Epidemiological designs
* Case-control studies
* Cohort studies
V- Survey research design
I- DESCRIPTIVE RESEARCH DESIGNS
The purpose of descriptive studies is to observe, describe, and document aspects of a situation as it naturally occurs, and sometimes to serve as a starting point for hypothesis generation or theory development.
a. Univariant descriptive design
To describe the frequency of occurrence of a phenomenon.
b. Exploratory design
Exploratory design is used to identify, explore, and describe the existing phenomenon and its related factors. In other words, it is not only a simple description or the frequency of occurrence of a phenomenon, but its in-depth exploration and a study of its related factors to improve further understanding about a less-understood phenomenon.
For example, an exploratory study to assess the learning needs of hypertensive patients visiting cardiac outpatient department (OPD) at Fortis Hospital, Mohali, Punjab.
c. Comparative design
Comparative design involves comparing and contrasting two or more samples of study subjects on one or more variables, often at a single point of time. This design is used to compare two distinct groups on the basis of selected attributes such as knowledge level, symptoms.
For example, ‘A comparative study on health problems among rural and urban older people in district Bikaner, Rajasthan’
II-CORRELATIONAL/EX-POST FACTO RESEARCH DESIGN
it is a research design where researchers study the relationship of two or more variables without any intervention. For example, this design was used for ‘A correlational study on the effect of smoking on lung cancer among people in New Delhi’
Types of Correlational Research Design
a. Prospective research design
A design in which the researcher relates the present to the future is a prospective research design. research design, researcher observes phenomena from cause to effect.
For example, a researcher conducting a prospective correlational study on effect of maternal infection during pregnancy on foetal development and pregnancy outcome.’
b. Retrospective research design
A design in which the researcher studies the current phenomenon by seeking information from past is a retrospective research design. In this the researcher links the present phenomenon with the past events.
For example, this design was used in ‘a retrospective correlational study on substance-abuse-related high-risk factors among traumatic head injury patients admitted in neurosurgery ICU of Dayanand Medical College and Hospital (DMCH), Ludhiana’.
III- DEVELOPMENTAL RESEARCH DESIGN
Developmental research designs are generally used as adjunct research designs with other research designs such as cross-sectional-descriptive, longitudinal-correlational research designs.
Two Types of Developmental Research Design
a. Cross-sectional design: Cross-sectional research design is one in which researcher collects data at particular point of time (one period of data collection). These studies are easier and more convenient to carry out.
b. Longitudinal design: Longitudinal research design is used to collect data over an extended time period (long-time study). Its value is in its ability to demonstrate change over a period of time
IV-SURVEY RESEARCH DESIGN
A survey is a research design which is used to collect information from different subjects within a given population having same characteristics of interest. If a survey is conducted on a sample of population, it is called sample survey, and if the entire population is involved, it is called a population survey, such as censuses, etc.
Types of the Survey
>depend on nature of phenomenon of the study
a. Descriptive survey: It is undertaken to describe the frequency of occurrence of a phenomenon rather than to study relationships.
b. Exploratory survey: It is the survey of a phenomenon, and its related factors, about which much is not known.
c. Comparative survey: Comparing and contrasting the existence of a certain phenomenon in two or more groups is done by comparative surveys.
d. Correlational survey: It is a study of the relationship between two or more variables in a natural setting without manipulation or control.
>Based on methods of data collection
a. Written survey: In a written survey, data are collected with the help of written, structured such as questionnaires, opinionnaires, etc.
b. Oral survey: Data in an oral survey is collected by using face-to-face or telephonic conversation or oral interview with respondents.
c. Electronic survey: When data is collected by using electronic means such as electronic-mail messages (Emails), web forms, mobile short-message services (SMS), etc., it is known as electronic survey.
ADVANTAGE OF NONEXPERIMENTAL RESEARCH DESIGN
* Nonexperimental research designs tend to be closest to real-life situations.
* Nonexperimental research designs are most suitable for the nursing research studies.
* Numerous human characteristics are inherently not subject to experimental manipulation
* There are many variables that could technically be manipulated, but manipulation is forbidden on ethical grounds.