Development phase IIIOrganizing the methodology

III. Methodology

1. Building Research framework2. Operationalization of the concepts3. Developing an argument 4. Selection of a Study design 5. Data collection method 6. Population and sampling7. Validity and reliability 8. Ethical consideration

1. Research framework

Research Framework

• Organize a spectacle to do the research• Demarcate the area of research • Conceptual frame work • Scientific validation • Prelude to making the research operational

STAGE 02• Categorize causes and effects • Use acceptable method – Previous studies– Discussions

• These groups become concepts of the research

Stage 2 – categorization

Problem Tree

Analyze the problem - Cause & effect analysis

Causes - reasons for the problem

– Infrastructure – ventilation , light , seating , small waiting and clinic

area

– Human resources – low number , lazy staff , untrained staff

– Methods – no method , ineffective method , old method

– Patients – lack of compliance and patience

Effects – results of the problem

inconvenience, poor quality , image of the hospital , risk for the

patients

Problem – overcrowding of the medical clinics

Research Frame work

2. Operationalization of the concepts

Development of the variables Indicators

Method

• The concepts needed to be make it measured to validate the research

• Organize the variation of the concept• Select variables from the sub causes or the

sub effects you identified

• Indicate the concept• Find the variables related to each concept • These could be taken from your causes or

effects identified in the problem analysis • Use the same main causes or main effects• Now use the Objective of what do you want to

do • Only concentrate the areas demarcated by the

objectives

Opreationalization of the concept Concept Indicator Variable Method

Human resource

The level TrainingAttitude Number

Methods Accuracy Appointment system Rules Regulations

Facility Quality LightingSpace

Equipments Usability Seats Tables

Overcrowding Number Space Patients

• List the variable • Define the variable • Make it independent • Find the indicator • This could be done by studying previous

research or acceptable methodology • Then find each one an indicator • Find the method of measurement –later in the

data collection • Next step is the identifying the best reaserch

design

What are Variables ?

• Variable

– “Characteristic of a person, object or a phenomena that takes different forms or that varies.”

– Variable two main types

• Numerical variables - takes Number form

–Weight , height ( 23 kg . and 100 cm)

• Categorical variables - category form

– Color , Race ( black , white and Sinhalese , Tamils , Muslims )

Selection of Variables

• Variable

– “Uses of variables

– To operationalize the reserch framework

– To construct questions

– To improve the validation of data and form tables

– To indicate variables in statistical form &

treatment

Classification of Variables

• According to the type, epidemiological, statistical variety

• Types

– Biological , physical, socio- economic ,events & service delivery

• Epidemiological

– Dependent

– Independent

– Confounding

– Background

Main Causative factor Smoking

Other factors Alcohol , occupation

Effect Lung Cancer

Problem – Dependent Main factors – Independent

Confounding –effect both Background factors Age, sex , race

Background – no direct effect

• Dependent

– Describe the problem of the study

• Waiting time

• Independent

– Describe the direct causative factors

• Availability of staff

• Efficiency of the staff

• Confounding

– These affects both dependent and independent variables

– They either weaken or strengthen them • poor infrastructure

• Background• Old age

• Language barrier

• Formulation of Variables

– Find contributory factors

– Rephrase

• Making variable neutral

• Long waiting time – “waiting time “

– Operationailize

• making variables measurable through indicators

– 1 hour - good

– > 1 hour to 2 hours- reasonable

– > 2 hours - poor

– Define

• To ensure consistency and remove confusion and bias

– “The time patient enters to the OPD clinic, up to seen by the consultant doctor”

– Scales measurement • Mnts. , Hours ,

Variables

The factors that have identified in problem analysis may be negative. By rephrasing it has to be made as neutral variable where it can take both negative and positive forms ;

• Long waiting time (-) - Waiting time• Absent of D (-) -Availability FD• Lack of supervision - Frequency of supervisory visit

• Poor knowledge of signs, causes and -Knowledge of sign, cause and Consequences TB consequence

b. Operationalizing Variable

• Making variable measurable• Some variables can be measured easily but some cannot be categorized easily. Measurable • categorization of variable presents as ‘Indicators’

• ‘Poor knowledge of pregnant mother mother’ - Factor

• Rephrase the Variable- Level of knowledge of pregnant mother • Operationalize Indicator • Correct answer to < 3Q – poor 4-6 -reasonable • > 7 – good

• Weight/age >80% std - Well nourished I

• 0-80% std - moderate malnutrition • > 60% std - severely malnutrition

c. Defining Variables & Indicators

• To ensure everyone understand the exactly what has been measured and to ensure consistency in the measurement, definition of variable and indicators are need.

• Ex. Waiting time – ‘when patient enters the front door of OPD until it is seen and a doctor or register or \ obtain a card’

• Experts comments : previous study variable and logical variable should be considered here.

Opreationalization of variables Concept Variable Indicator

Human resource TrainingAttitude Number

Participation for the

Methods Appointment system Rules Regulations

Facility LightingSpace

Equipments Seats Tables

Overcrowding Space Patients

3. Developing an argument

Hypothesis

• Main problem becomes main concept • Other groups of causes become the directing

concepts • This is the basis for the argument or

Hypothesis

Based on the conceptual framework you • Develop a logical argument for the research • Positive argument – Hypothesis • Negative argument - null hypothesis • In the research what you do is prove or

disapprove the hypothesis

Hypothesis • H01 – There is definitive overcrowding of CNTH• H 02 – Human resources will have Direct effect

on overcrowding • H 03 – Infrastructure will have Direct effect on

overcrowding • H 04 – Equipments will have Direct effect on

overcrowding • H 05 – Supplies will have Direct effect on

overcrowding

4. Research designs

1. Selection of the study design Designing the study - Select a type of design

A. Reason• Basic and applied

B. Time • Cross sectional and Longitudinal- Retrospective , prospective

C. Scope• Descriptive ,

D. Intervention• Experimental , non -experimental

E. Quantification & qualification

f• C

A. Reason Basic and Applied

This is classified according to the reasons for conducting the research

• Basic – Basic ………………find new knowledge – Vaccine for Malaria / AIDS

• Applied – Applied ………….find answers to day to day

problems – Health needs/ wants

Research can be:

• Basic or Pure: – Acquire new knowledge and further research– May be laboratory-based

• Applied – Associated with solving practical issues and answering

questions– Clinically-based

• Most nursing research is applied

B. Time Cross sectional & longitudinal

This is categorized as per the time span • Cross sectional• One point of time• Snap shot • Maximum Months

• Longitudinal• Spread over time• long term• Years

Cross sectional studies • Quantify the distribution of certain variables in a study population at one

point of time ………………(snap shot)• It will include

– Physical characteristics of people, environment; prevent survey of leprosy, evaluation coverage (immunization, ……..)

– Socio-economic characteristics of people; age, education, marital status, no. of children and income.

– Behaviour of people ….. and opinion, that may help to explain the behaviours (….. studies)

– Events that occur in population – death, birth, marital, migration example : census – cross sectional survey covering total population– Disease and distribution – prevalence survey– Health programmes

Longitudinal studies Retrospective & Prospective

Categorized according to a point of collection

– Retrospective - ………..Past <-------- Present– Collect a group of patients with lung cancer and

see the their exposure to smoking – Prospective ……………. Present -------- >future – Collect a group of people who are smoking and

asses the development of lung cancer over period of time

• Descriptive• Exploratory• Explanatory• Experimental• Methodological

C. Scope/ purpose

C. Scope - Descriptive & Exploratory

This is categorizes as per the purpose • Descriptive – Describe the subjects / situation – Questions asked and answers are need

• Exploratory – Explore the situation – Case studies – Limited scope

Descriptive studies

• They describe relevant situation, people, programme or

events

• Majority of the studies performed are descriptive studies

• Systematic collection and presentation of data to give a clear

picture of a particular problem or situation

• Questions are asked to find out answers on the above

mentioned situations

• who, when, where, why , & what to do

Descriptive• Present-oriented research that seeks to accurately

describe or analyse the facts obtained in relation to the problem under study. It may lead to theories or hypotheses to test experimentally

• For example: responses to pain following surgery or changes in behaviour with an increase in age

Questions asked answers sought• Who? -Personal characteristics• Why?-Reason/association• Where - Distribution• What to do?-Suspect action• When -Time/season or future studies

Descriptive studies

Exploratory

• Research that explores the dimensions of a phenomenon (concept) or

• Develops/refines the hypothesis about relationships between phenomena

• For example: Experiences of hospitalisation of a long term patient

Explanatory• Research that attempts to explain how

humans develop/change according to a certain situation

• For example: the phases of development of father involvement in pregnancy

Experimental

• Research that tests a hypothesis or hypotheses by setting up a controlled situation and then manipulating it to determine the effect of the manipulation. The design consists of control and experimental groups which are tested before and after the manipulation of the group or groups

• For example: types of skin graft used on burns patients and resulting scarring

Exploratory studies

• This is a small scale study performed to clarify a problem or situation.

• Mostly performed in management problems to analyze a situation.

• Rapid appraisal method for management.

• Interviews and comparison of a problem is performed.

– Ex. Needs of HIV AID patients of various gender groups and to

prioritize resources allocating (here the various needs are compared, a

rapid appraisal is performed)

Methodological

• Research that is designed to develop or refine procedures for obtaining, organising or analysing data

• For example: developing an instrument for measuring anxiety in patients

Match ups

• The type of research must match the purpose of the research.

• No good measuring something if the purpose is to explain or explore it.

• No good explaining something if the purpose is to measure it.

Quantitative Research• Focussed on the physical and empirical or

measurable world – objective• A systematic logical process used to answer

questions about measurable concepts – very structured and formal

• Control and manipulate events maybe in a laboratory setting

• Numerical data is collected and analysed using statistics

Qualitative Research

• Focussed on the subjective nature of humans• A systematic and interactive approach • The investigation of phenomenon (concepts), typically

in an in-depth manner for the purpose of describing or explaining events

• Study people in their natural/real setting – their lived events/experiences

• Multiple data collected and analysed for themes, patterns, classifications or categories

Comparison – why both?

• Complement each other• Generate different kinds of knowledge• Bother require researcher expertise• Both need systematic planning, data

collection and analysis • Both are necessary in Nursing practice

Combined

Today studies sometimes combine elements of both qualitative and quantitative research.

D. Experimental & non-experimental studies

This is categorized as per the research design – Experimental …….. Interventional– Non experimental …………non interventional/

observation – Majority are non experimental

Experimental studies

• Randomly select to two groups.

• One is subjected to intervention (or experiment) and the

other without intervention. The outcome of intervention is

obtained by comparing two groups

– (the outcome : effect of the intervention on the problem

or the dependent variable)

• These studies actually prove causation

Experimental studies

• Classical experimental studies have 3 characteristics

1. Manipulation - Researcher does something to one group of subjects in

the study.

2. Control -The researcher introduce one or more control groups to compare

with the experimental group

3. Randomization -The researcher randomly assign subjects to control and

experimental groups (given equal chance for selection to either group)

D. Qualitative & Quantitative Research

Selection

• The decision of whether to choose a quantitative or a

qualitative design is a philosophical question.

• Which methods to choose will depend on the:

– Nature of the project,

– The type of information needed the context of the study

– The availability of recourses (time, money, and human).

Qualitative research

• Qualitative Research is collecting, analyzing, and

interpreting data by observing what people do and

say.

• Qualitative research refers to the meanings,

concepts, definitions, characteristics, metaphors,

symbols, and descriptions of things.

Qualitative research

• Qualitative Research is collecting, analyzing, and interpreting data by

observing what people do and say.

• Qualitative research refers to the meanings, concepts, definitions,

characteristics, metaphors, symbols, and descriptions of things.

• More subjective than quantitative research

• Uses different methods of collecting information,

– Mainly individual, in-depth interviews and focus groups.

– The nature of this type of research is exploratory and open-ended. Small numbers of

people are interviewed in-depth and/or a relatively small number of focus groups are

conducted.

• Quantitative• Objective• Research questions: How many?

Strength of association?• "Hard" science• Literature review must be done

early in study• Test theory• One reality: focus is concise and

narrow• Facts are value-free and unbiased• Reduction, control, precision• Measurable• Mechanistic: parts equal the

whole• Report statistical analysis.

• Qualitative• Subjective• Research questions: What? Why?• "Soft" science• Literature review may be done as

study progresses or afterwards• Develops theory• Multiple realities: focus is

complex and broad• Facts are value-laden and biased• Discovery, description,

understanding, shared interpretation

• Interpretive• Organismic: whole is greater than

the parts

• Quantitative• Basic element of analysis is numbers• Researcher is separate• Subjects• Context free• Hypothesis• Reasoning is logistic and deductive• Establishes relationships, causation• Uses instruments• Strives for generalization• Generalizations leading to prediction,

explanation, and understanding• Highly controlled setting:

experimental setting (outcome oriented)

• Sample size: n• "Counts the beans"

• Qualitative• Report rich narrative, individual;

interpretation. Basic element of analysis is words/ideas.

• Researcher is part of process• Participants• Context dependent• Research questions• Reasoning is dialectic and inductive• Describes meaning, discovery• Uses communications and

observation• Strives for uniqueness• Patterns and theories developed for

understanding• Flexible approach: natural setting

(process oriented)• Sample size is not a concern; seeks

"informal rich" sample• Provides information as to "which

beans are worth counting"

Combination of both • It is a combination of two types of research. It is also called pluralistic

research.

Advantages of combining both types of research include:• Research development (one approach is used to inform the other, such as

using qualitative research to develop an instrument to be used in quantitative research)

• Increased validity (confirmation of results by means of different data sources)

• Complementarity (adding information, i.e. words to numbers and vice versa)

• Creating new lines of thinking by the emergence of fresh perspectives and contradictions.

5. Data collection method

1. Decide how to collect data - Data collation method

Data Collectionmethods

Data collection

• A systematic data collection is necessary for the success of the research,

• Main methods – Using available data– Observing– Interviewing– Administering written questionnaires– Focus group discussion & Depth interviews – Other data collection techniques

A. Using available information

• Locating sources of and retrieving information is important starting point in data

collection effort.

• Health information data, census data, published or unpublished data, publication

in archives, and libraries

• Advantages :

– This method is relatively inexpensive, permits examination of past trends

• Disadvantages:

– Not easily accessible for data, incompleteness of data and need to

take permission

B. Observing

• Observation of human behaviour can be done

• use for small scale studies

• Observation can be perform on objects or situations ( cleanliness of a ward)

• Observation needs defined measurements and standards

• Adv.– It yield, more accurate information on behaviour than other techniques and also can use to verify

data collected from other techniques

• Dis Adv. – But it is time consuming and relatively expensive

– Ethical issues and privacy problems also observer bias seen throughout training of research

assistance is done.

C. Interviewing• Oral questioning of respondents, either individually or as a group.• The responses are recorded.• This could be performed with high degree or low degree, flexibility • High degree of flexibility:

– structured or unstructured method of interviewing from. informants. – This is good for situation analysis and often used in exploratory studies and case

studies.

• Less flexible method as – when researcher is knowledgeable of the answers and used for large scale studies

• Advantage : – Can be used with literates, permit, clarification of Q and expect to have group response

> written Q

• Disadvantage:– Presence of interviewer can influence respondents

D. Written Questionnaires

• Are presented to study subjects with the response in written form. Also named as self-administered questionnaires.

• This could be performed by sending questionnaire by post or gathering people to one place and administered by giving written or oral instructions. Also could hand deliver and collect later.

• Questions can be open ended or close ended (describe in detail later)• Advantage :

– Less expensive, creates honest responses, does not require research assistance, eliminated bias

• Disadvantage :– Cannot be used to literate responses.– Questionnaire may be misunderstood , low rate of response

Interviewer & self administrated questionnaires

• Interview and self – administered questionnaires are the most commonly used data collection methods.

• The questions to ask in the development of these are;– What do we want to know according to the objectives and variables and do we need any

other technique.– From whom are we going to ask questions and what techniques to us– Do we need to use with loosely structured questions when topic is not understood

correctly – Is our informants literate or illiterate (if literate it should not be self-administered)– How large is the sample to be interviewed (smaller studies open ended and larger

studies highly structured, shorter questions)

Types of Questions

• Open ended • Closed ended

Open ended

• Permit free responses that could be recorded in respondent, own word, the respondent is not given any possibility to choose from.

• This is useful to obtain information on;– Facts with which the research is not familiar with – Opinion, attitude and suggestions of information

and requirement– Sensitive issues

Closed ended• Offer a list of possible opinion, or answers from which the respondents

must choose. In this one has to ;• Offer list of options that are exhaustive and mainly exclusive• Keep no. of options minimal as possible• Closed questions are useful when the range of possible responses, known• Its also used when one only interpret in certain aspects on an issue and

does not want to waste time with the respondent.• It also could be used to asses respondent, opinion by choosing rating

point on a scale (ex. very useful, useful, not useful)

Comparison on Open & closed questions

Open ended • Exploration of issues not known

during planning stage• Use for sensitive issues • More valid answers • Skilled interviewer need • Analysis time consuming• Interviewer bias • Needs experienced trained

people

Close ended • Answers can be recorded quickly• More general issues • General comments• Used for literate • Analysis easy • Leading questions can cause bias • Use closed questions in

combination with open

Steps in designing a questionnaire

– This takes in form of several drafts1.Content 2.Formulating questions 3. Sequencing 4. Format 5.Translation

The method 1. Content

– objective and variable

2. Formulating questionnaire

– Produce one or more questions that will provide the information for each variable.

– Then check whether each questions measures one thing at a time. – Avoid leading question.– Formulate control question to cross check* on ‘difficult’

questionnaire. – Avoid word with double meaning or defined meaning and

emotional words ( ex . Wasting, lazy, unhealthy)

3. Sequence of questionnaire; • Design your interview schedule or questionnaire to be ‘consumer friendly’• Make sequence of questionnaire more logical and make it more natural

discussions• Background variable should be asked later • Start the non-controversial questions and post more sensitive questions later. • Use simpler everyday language. Make the questionnaire short as possible.

4. Formatting the questionnaire;• Interviewing data : location: name (Optional) respondent and interviewer. • Sufficient space for open ended questionnaire. Boxes of pre-categorized answers,

placed in consistent manner ((® side of page)• Marking for computer codes.• Questionnaire should be consumer and user friendly.

5. Translation ;• To the local language and cross check.

E. Focus Group Discussions

• Group discussion of 6-12 persons, guided by a facilitator. The group interact with each other with relation to concepts, perception and ideas.

• Uses of FGD, are;– Problem analysis in research– Formulation of questionnaires– To ensure community knowledge, benefit and attitude regarding a problem– Development of measures to health education programmes– To explore controversial issue

• Preparation for FGP– Recruitment of participant: These people should from similar backgrounds for

which the problem to be discussed.– Physical arrangements: Place arranged which is conducive for discussions

• Preparation for FGP

– Recruitment of participant: These people should from similar backgrounds for

which the problem to be discussed.

– Physical arrangements: Place arranged, conducive for discussions

Ex. Circular chair arrangement)

– Preparation off a discussion guide. Written guideline with open ended question

• Conducting the session

– A recorder and a facilitator of the group identified

– The facilitator must introduce the pupil, encourage discussion involvement, build report, empathize,

avoid being placed in the role of expert, control rhythm of the discussion.

– The recorder should note down participation characters, general description of participants, group

dynamics, opinions, emotional aspects and vocabulary used

• Number of sessions

– 1 ½ hours duration, the number is according to the need

• Analyze the Results

• The facilitator and Recorder review

• Full report is given

• Categorize each topic

• Summarize in matrix, flowchart in a meaningful way.

• Select most useful idea

• Report writing

• Single person – longer hours – Depth Interviews

5. Other data collection techniques

• Nominate group techniques• Delphi• Life histories• Scale• Essay• Case studies• Mapping

1. Nominal Group Technique

• This is good to obtain census from a group in decision making • Interventional Individual ideas write on paper• Display list produced and then disused• Vote and rank the ideas• Summarize the ideas• Discuss the results• Second voted and reviving• Voting• Selection .

2.Delphi Techniques• This is similar to NGT but people do not meet they

communicate via questionnaire. Its time consuming and participants should have god written communication skills.

3. Life Stories– Interviewing of life stories, suited for reproduction pattern

woman feeling about marriage, conceptive and childbirth• 4. Scales : – These are highly structured interviews and are of high

standard. Good for healthy behavior, psychiatric illness and in joint descriptive studies and population survey, in common groups.

5. Essays.These analyst the difference in belief concerning illness, health behavior (prior to

intervention).

• 6. Last Studies :– Obtained investigation of few people, commonly or particular

situation• 7. Manpower :

– It visually displays relationship and resources its important in pre-stage sampling

8. Rapid Appraisal Techniques (sounding)– Quick, low cost, less accurate survey, to clarify unclear areas of a

problem (commonly done in pilot phase of research)

9. Participation Research:– All status of research is planned and conducted by the researcher

and the …….. commonly together• Ex. Community Dx - with people and for people

6. Improving the Validity and reliability of data

1. Population and sampling2. Validity and reliability 3. Ethical consideration

Validity & Reliability

• Deriving Valid and Reliable Conclusions• When research design is selected all attempts

to make it to be valid and reliable.• Validity – means conclusive are true• Reliability – means in repeated attempts,

conclusion have to be the same

Eliminating threats to validity in selecting research design;

– By selecting appropriate design this could be performed

– Descriptive studies : By sampling, the information is collected and findings used to make conclusion about the population. Proper sampling is the key to success.

Bias in information collection

1. Defective Instrument

• Questionnaire : – The questions placed in logical order and vaguely phrased. Also

fixed/closed questionnaire on the topics less known, open ended questionnaire without guidelines

• Weighing scale substandard

2. Observer bias

• In observation & interviews critical information may be missed

• Therefore to reduce this – organizing observation guidelines for structured

interviews– training & practicing of data collectors

3. Effect of the interviewer on the informant

• Respondent may mistrust the interviewer and dodge questions.

• This bias can be reduce by adequately informing the subject and assuring them about information collected are kept confidential.

• Careful selection of interviewers is also important.

Ethical Consideration

• The data collecting technique should will not effect any emotional or mental harm to study subjects, such as asking sensitive questions that may violate their privacy, observing informats, without their knowledge and failing to respect certain cultural values, traditions etc.

• Remedy for these are– Obtaining permission before study begins, not exploring sensitive

questions before developing a good relationship with the informant– Ensuring confidentiality of the data obtained. (name and

address)

6. Population and sampling

Identify the Population & the sample - Sample selection

6. Population and Sampling

Sampling • Population & sample

• Sampling – Selection of number of study units from well defined study population

• Study Problem – Malnutrition in Preschool children in Gampaha

• Study population – All children below 05 years in Gampaha district

• Study unit – one child below 05 year in Gampaha district

• Representation– All important characteristics of the population should be in the selected sample

• Study frame work – All the names of the students below 5years in Gampaha

Representativeness

– The research draws conclusion to the whole study population

– Drawing of the sample should be representative of that population from which it is drawn

Questions and definitions

• In sampling the following questions should be answered. – What is the group of people (or population) from which draw a

sample?– How many people do we need in our sample?– How will these people be selected?

• Definition of study population is important– According to age and residence.

• Study population consists of study units which we define according to the problem to be investigated.

Sampling Methods

• Availability of Sampling frame – probability sampling

– Listing of all the study units that compose study population.

– Probably sampling methods

– Each study unit has adequate chance or at least known probability of being

selected in the sample

• Non-availability of sampling frame – non probability sampling

– researcher will use non probably sampling methods

Types of sampling

• Probability – Simple random

– Systematic random

– Stratified

– Cluster

– Multistage

• Non Probability – Convenient

– Quota

Non probability sampling • Convenient

– For convenience sake, study unit, that “happen to be available at the time of data collection” are selected in the sample. (Ex. Patients attitude in a Family Planning clinic)

– Un-representativeness is the main draw back in convenient sampling where over selection, under selection and missed selection seem. These deficiencies are impossible to adjust.

• Quota

– It ensures certain number of sample units from different categories with specific characteristics that appear in the sample.

– The investigator interviews as many people in each category of study unit until his quota is filled.

– Opinion of the health professionals regarding election

A. Probability sampling

• It involves random selection procedures to ensure that each unit of the

sample is chosen on the basis of “ chance”.

• Therefore all units of the study population have an equal or known

chance of being selected in the sample.

• ‘Sample Frame’ is important• types

1. Simple random2. Systematic random3. Stratified4. Cluster5. Multi-stage

1. Simple Random Sampling

• Make numbered list of sample units

• Decide on the sample size

• Then select the sample by:

– lottery

– table of random numbers

– Computer generated numbers

2. Systematic Sampling

– Individuals are chosen at regular intervals total sample frame nos. from the sampling frame.

– First randomly select a number and then the regular choice is performed (according to sample size)

– Pop – 1200 Sample size-100 ( 1200/100)

Sample interval – one in 12th person

3. Stratified Sampling

• This method is useful when a sample needs to include “Representative

groups of study units with “specific characteristics”

– Urban/Rural/age limits

• Here the sample frame is divided into groups of “strata “according to the

characteristics.

– Urban / Rural

• Then random or systematic sample of pre- determined sample size

randomly from “each group” ( “stratum” )

– Example : “Ethnicity in Sri Lanka” – strata - 80% Singhalese , 12% Tamils ; 6% Muslims; 2%

others

• This is only possible if the “proportion of Study population” is

known in each group.

• Advantage of stratified sampling is that we can take relatively

large sample from relatively sample group .

• This allows the researcher to obtain a larger sample that we

could draw conclusions (without obtaining a larger group)

3. Stratified Sampling

4. Cluster Sampling

• The selection of “groups” in study units instead of “individual study units”.

• Clusters are often geographic unit (districts, villages) or organizational units, schools, clinics, training units).

• Groups of students available (ex; villages or schools)

• Number of these groups are randomly selected.

• This is useful without of sampling frame

• Ex. ‘KAP study or FP in rural communities- list of all the villages

4. Multi-stage Sampling

• Procedure is carried out in phases and usually involves more than one

sampling method.

• This is frequently done in “community studies”

• Ex. Four stage sampling method for ‘cleanliness of latrines’ district

comprised of 6 “wards” and each ward has 6-9 villages

• Select 3 wards from 6 by simple random sampling

• For each selected ward select 5 “villages” by simple random

• For each village select 10 “households” by systematic random

sampling

• Go to the center of the village

– Choose a direction in random way – toss a coin

» Walk in the chosen direction, select every 3rd household

(depending on the size of the village)

» Decide before hand whom to interview (ex. Oldest)

4. Multi-stage Sampling

Selection of Sample size

• Rough guide – 10% of population • Equations and statistical methods of

calculating sampling size

Validity

• Standardization of the research

• Validity

– How accurate the measured variable ACCURACY

– Threats to validity

• History

• Subject loss

• Selectivity

• Hawthorne effect

How to reduce threats of Validity

• Control group• Randomization • Pre-testing • Knowledge of events

Activity III

• Please do select the proper methodology for your proposed research