Introduction to research 1703423-2

Research designs

Dr Naiema Gaber

Learning Objectives

At the end of the discussion you should be able to do the following:

1-Define and explain the *concept of a research design*Purposes of research design *Characteristics of good design

2-Identify and explain the different categories and sub-categories of research design

At the end of the discussion you should be able to do the following:

1-Define and explain the *concept of a research design*Purposes of research design *Characteristics of good design

2-Identify and explain the different categories and sub-categories of research design

Introduction

• The research design provides the back bone structure of the study, it supports the study and hold it's together.

Def: • The research design refers to the researcher

overall plan for answering the research question or testing the research hypotheses

Research Design

A research design is: • a framework for the research plan of action.

• a master plan that specifies the methods and procedures for collecting and analyzing the needed information

• a strategy for how the data will be collected.

Purposes of Research Design

• It provides the scheme for answering research question.

• It maintains control to avoid bias that may affect the outcomes.

• It organize the study in a certain way defending the advantages of doing while being aware and caution about potential disadvantages

Characteristics of good design

• 1- Appropriateness to the research question.• 2- Lack of bias.• 3- Precision.• 4- Power.• Research design can be either quantitative or

qualitative. Both designs complement each other because they generate different kinds of knowledge that are useful in nursing practice.

Designs for nursing research

The four types most commonly used in nursing are:

* descriptive / exploratory survey *correlational*experimental*Quasi Experimental Design

A- Descriptive: (exploratory survey) studies

• Its purpose is to provide a picture of a situation as it naturally happen,

• No manipulation variable is involved• Some studies contain two variable, others

may include multiple variables. • They use this design to search for accurate

information about the characteristic s of particular subject, group, and event or about the frequency of the phenomena.

• Advantages of descriptive:• The great deal with information obtained

from large population and is surprisingly accurate.

• Disadvantages of descriptive: • The information collected is very brief and

superficial.• It is a time consumer process

B- Correlational design

• It examine relationships between or among two or more variables in a single group.

• It requires a large sample size. Subjects are not divided into groups

• The correlational design doesn’t test the cause and effect relationship

Advantages OF Correlational studies:

• An increase flexibility when investigating complex relationship among variables.

• An effective and efficient method of collecting a large amount of data about an issue of interest.

• Exploring a relationship between variables.

Disadvantages 0F Correlational studies • The researcher is not employing the randomization in the

sampling procedures. • The researcher is unable to determine the causal

relationship between the variables because of lack of manipulation, control and randomization.

C) Experimental Research Design• Test a causal hypothesis (Cause and effect

relationship) between the intervention or treatment and the outcomes

Elements of true experiment design:

1- control group 2-sample randomization 3-manipulation of the independent variable.

Types of Experimental DesignThere are 3 types of experimental design:-1-Pre test – post test control group design:-• the experimental and control groups are both

randomly assigned from the sample that was randomly selected.

• The treatment is under control of the researcher, the dependent variables is measured twice before and after manipulation of the independent variables .

• the researcher observes the two groups to determine effect of manipulation (post test).

Advantages of Pre test – post test control group design-:

• Threats to internal validity are minimized (control group )

• Presence of randomization leads to equal chance for the subject to be selected.

• Allow the researcher to examine changes occurs.• Disadvantages :-• The results can not be generalized on both

groups.• Mortality can affect one group rather than the

other

2-Post Test Only Experimental Group Design:

• The pre test can not be established, and also subject response to post test can be altered by the effect of the pre test, so post test only is performed.

Advantages:• Random assignment decreases the threats to

validity.Disadvantages• Without the effect of pre test the researcher

become unable to determine the effect of the treatment received.

3-Solomon four groups of experimental design

• Four groups can be used one experimental and three are control, some times are divided equally two control and the other are experimental .

• It is a stronger design than the post test only but require so complicated statistical analysis.

• Advantages• Allow the examiner to examine the effect of the

pre test on the post test. • Disadvantages• Mortality can affect the results.

General Advantages of Experimental Design

• Are most appropriate for testing the cause and effect relationship between the variables.

• Most appropriate for testing hypothesis.

General Disadvantages of Experimental Design • For some ethical reasons manipulation can

not be achieved especially on the human studies.

• Pre test can affect the response of post test.

D) Quasi Experimental Design-:

• Quasi experiment is research design in which the researcher initiates an experimental treatment but some characteristic of true experiment is lacking either control or randomization.

• it also used to test cause and effect relationship, the basic problem with the quasi experiment is the weakened confidence in making causal assertion so it is usually exposed to the subject contamination.

• Example: examining differences in the amount of pain that the patient feel during painful procedure and the effect of nursing intervention on the experimental group. It might be impossible to pretest the amount of pain

How and When to use Quasi-experimental research

• Used when you have control over the “when and the whom of measurement”, but lack control over the “when and to whom of exposure.”(complete control is not possible)

• Common in educational research.

COCLUSION

• A research design is a master plan that specifies the methods and procedures for collecting and analyzing the needed information.

• It is a strategy for how the data will be collected. • It provides the scheme for answering research

question(s).• It maintains control to avoid bias that may affect

the outcomes.

The most common types of Research design used in nursing are:

* descriptive / exploratory survey *correlational* True experimental*Quasi Experimental

Feedback questions

1- Pre- post- test design is – a- descriptive– b- correlated– c-experimental– d- quasiexperimental

C

2- A study to determine the effect of lake of sleep on attention span the day following for second year students.– This is an example of which type of research design– a- descriptive– b- correlated– c-experimental– d- nonexperimental

(C)

3- The quasi-experimental design does not include• a- manipulation of independent variable or

control• b- random sample or Control group and • c- random or manipulation of independent

variable• d- manipulation of independent or dependent

variables

• (b)

4- The most appropriate research design for testing the cause and effect relationship between the variables is.

a- experimentalb-correlationalc-descriptived-qualitative

(a)

Mach the name of design in column A with that corresponding in definition in column B

A B------ 1-descriotive study adequacy of

entral feeding for pt on mechanical ventilation

------ 2- correlative can miss controlling the sample

------ 3- experimental is there a relation between smoking and lung cancer

------ 4-quasiexperimental the effect of chemotherapy in vomiting

Mach the name of design in column A with that corresponding in definition in column B

A B---a--- 1-descriotive a- study adequacy of

entral feeding for pt on mechanical ventilation

---c--- 2- correlative b- can miss controlling the sample

---d--- 3- experimental c- is there a relation between smoking and lung cancer

---c--- 4-quasiexperimental d- the effect of chemotherapy in vomiting

THANK YOU