OVERVIEW OF QUANTITATIVE OVERVIEW OF QUANTITATIVE REASEARCH METHODOLOGYREASEARCH METHODOLOGY

Underpinning PrinciplesUnderpinning Principles

EVERY MINUTE IN THE EVERY MINUTE IN THE WORLDWORLD• 1 woman dies from a pregnancy-related 1 woman dies from a pregnancy-related

causecause

• 380 women become pregnant380 women become pregnant

• 190 of these women did not plan or do not 190 of these women did not plan or do not wish to be pregnantwish to be pregnant

• 110 women experience a pregnancy-related 110 women experience a pregnancy-related complicationcomplication

• 40 women have an unsafe abortion40 women have an unsafe abortion

SourceSource: WHO, UNICEF, UNFPA: WHO, UNICEF, UNFPA

Myths?Myths?

• Quantitative data analysis is simplerQuantitative data analysis is simpler

• Quantitative research findings are Quantitative research findings are difficult to understanddifficult to understand

• Quantitative research doesn’t tell the Quantitative research doesn’t tell the ‘real’ story ‘real’ story

• Quantitative research gives a ‘true’ Quantitative research gives a ‘true’ picture – offers factspicture – offers facts

DefinitionsDefinitions

‘‘a formal, objective, systematic a formal, objective, systematic process in which numerical data are process in which numerical data are utilized to obtain information about utilized to obtain information about the world’the world’

Burns and Grove, 1987.Burns and Grove, 1987.

DefinitionsDefinitions

‘‘objective and value free collection of objective and value free collection of data in controlled settings following a data in controlled settings following a predetermined research design’predetermined research design’

Carter, 1996 in Cormack.Carter, 1996 in Cormack.

PositivismPositivism

• Quantitative approach stemmed from Quantitative approach stemmed from logical positivist logical positivist school of philosophyschool of philosophy

• Belief that the world could be viewed as an Belief that the world could be viewed as an object – with laws and principles waiting to object – with laws and principles waiting to be discovered through be discovered through objectiveobjective research research

• Once these rules/laws/principles were Once these rules/laws/principles were measured and quantified, it was possible measured and quantified, it was possible to make sound, reliable to make sound, reliable predictionspredictions

Measuring RealityMeasuring Reality

• From a quantitative researcher perspective From a quantitative researcher perspective the world is seen as stable and predictable – the world is seen as stable and predictable – the ‘truth’ is out there, and it is measurablethe ‘truth’ is out there, and it is measurable

• Requires precise measurement tools which will Requires precise measurement tools which will generate numerical data which can then be generate numerical data which can then be subjected to various statistical analysissubjected to various statistical analysis

• Data can then be presented in a manageable Data can then be presented in a manageable format – tables, charts, percentages etc.format – tables, charts, percentages etc.

• From here the goal of quantitative research From here the goal of quantitative research can be achieved: can be achieved: generalizability.generalizability.

SamplingSampling

• It is unusual to be able to collect data It is unusual to be able to collect data from the entire from the entire populationpopulation

• We usually work with a We usually work with a samplesample that that representsrepresents the population the population

• We can then We can then generalisegeneralise from this from this representative sample representative sample back to theback to the populationpopulation

SamplingSampling

• Usual way of selecting a sample is through Usual way of selecting a sample is through a a randomised selectionrandomised selection from the from the population – a population – a sampling framesampling frame

• In a random sample every individual in the In a random sample every individual in the population has an population has an equal chanceequal chance of being of being chosen e.g. random numbers.chosen e.g. random numbers.

• Stratified samplingStratified sampling is used if you have a is used if you have a good idea which variables might influence good idea which variables might influence the outcome e.g.. voting and social classthe outcome e.g.. voting and social class

Threats to Generalizability or Threats to Generalizability or External ValidityExternal Validity• Selection Selection – findings being specific to the – findings being specific to the

group/phenomenon studied group/phenomenon studied • Setting Setting – findings being specific to, or – findings being specific to, or

dependent on, the particular context in which dependent on, the particular context in which study took placestudy took place

• History History – specific and unique historical – specific and unique historical experiences may determine of affect the experiences may determine of affect the findingsfindings

• Construct effects Construct effects – the particular constructs – the particular constructs studied may be specific to the group studiedstudied may be specific to the group studied

LeCompte and Goetz, 1982.LeCompte and Goetz, 1982.

ReductionismReductionism

The rigorous process of ‘systematically The rigorous process of ‘systematically reducing or breaking down complex reducing or breaking down complex information or situations into their information or situations into their simpler component parts in an simpler component parts in an attempt to understand the whole….the attempt to understand the whole….the whole is the sum of the parts and the whole is the sum of the parts and the parts organize the whole’parts organize the whole’

Carter, 1996 in Cormack.Carter, 1996 in Cormack.

ObjectivityObjectivity

• Traditionally exemplified by the Traditionally exemplified by the experimental approach experimental approach

• Objectivity is achieved by the Objectivity is achieved by the researcher remaining researcher remaining detacheddetached from the study and rigorously from the study and rigorously avoiding any intrusion of their own avoiding any intrusion of their own perceptions and bias.perceptions and bias.

VALIDITYVALIDITY

• VALIDITYVALIDITY – to what extent does the tool measure what it – to what extent does the tool measure what it claimsclaims

• Construct validityConstruct validity – e.g. is an IQ test really a measure of – e.g. is an IQ test really a measure of intelligence or something else? Perhaps the ability to do IQ intelligence or something else? Perhaps the ability to do IQ tests?tests?

• ContentContent – does my tool (e.g. questionnaire) capture the full – does my tool (e.g. questionnaire) capture the full extent of intelligence, or just some aspects? E.g. does it extent of intelligence, or just some aspects? E.g. does it include spatial intelligence?include spatial intelligence?

• Face Face – does it look as though it is measuring intelligence – does it look as though it is measuring intelligence (we may want low face validity)(we may want low face validity)

• Predictive Predictive – does the score on the tool predict behaviour? – does the score on the tool predict behaviour? E.g. does a high IQ score predict who will do well at school?E.g. does a high IQ score predict who will do well at school?

RELIABILITYRELIABILITY

• RELAIBILITYRELAIBILITY – the extent to which the test – the extent to which the test measures consistently under different conditionsmeasures consistently under different conditions

• Split-test reliabilitySplit-test reliability – a measure of internal – a measure of internal reliability – if the test is split into two parts, will reliability – if the test is split into two parts, will each part produce similar scores?each part produce similar scores?

• Test-retest reliabilityTest-retest reliability – a measure of reliability – a measure of reliability over time. If the test is readministered at a later over time. If the test is readministered at a later date, will each administration of the test produce date, will each administration of the test produce similar scores?similar scores?

• Inter-rater reliabilityInter-rater reliability – a measure of reliability – a measure of reliability between different test administrators. If two between different test administrators. If two different people both administer the test, will different people both administer the test, will each produce similar scores?each produce similar scores?

Types of Quantitative Types of Quantitative ResearchResearch

• DESCRIPTIVE RESEARCHDESCRIPTIVE RESEARCH – aims to – aims to describe the characteristics of describe the characteristics of individuals and groups. Can be used individuals and groups. Can be used to determine the frequency with to determine the frequency with which a particular variable occurs which a particular variable occurs e.g. breastfeeding rates following a e.g. breastfeeding rates following a Caesarean birth.Caesarean birth.

Types of Quantitative Types of Quantitative ResearchResearch

• Questionnaires Questionnaires – info. through – info. through written responses (face to face, written responses (face to face, postal, telephone or e-mail). May be postal, telephone or e-mail). May be highly structured (closed or fixed highly structured (closed or fixed alternative questions) or semi-alternative questions) or semi-structured (open-ended questions). structured (open-ended questions). Type of question determined by Type of question determined by nature of information/data required. nature of information/data required.

ContCont

• Interviews Interviews – verbal interaction – verbal interaction between researcher and respondentbetween researcher and respondent

• Vary in degree to which they are Vary in degree to which they are structured – but usually clearly structured – but usually clearly structured to ensure exactly the structured to ensure exactly the same questions are asked to all same questions are asked to all respondents.respondents.

• Responses are pre-coded and results Responses are pre-coded and results tabulatedtabulated

ContCont

• Observation Observation – not exclusive to – not exclusive to quantitative research. Use of check-lists to quantitative research. Use of check-lists to indicate occurrence of a particular indicate occurrence of a particular behaviour or event, and rating scales to behaviour or event, and rating scales to provide more info. on observable provide more info. on observable behaviour or event.behaviour or event.

• Correlation studiesCorrelation studies – systematic – systematic investigation and explanation of investigation and explanation of relationship between variables.relationship between variables.

RANDOMISED CONTROL RANDOMISED CONTROL TRIALSTRIALS• RCT RCT – viewed as the – viewed as the ‘gold standard‘gold standard’ of ’ of

research i.e.. the method of choice if you research i.e.. the method of choice if you seek to do quality research.seek to do quality research.

• A variant of true A variant of true experimentation experimentation involving the use of a involving the use of a control group. control group. Participants are Participants are randomly assignedrandomly assigned to an to an experimental group which follows a experimental group which follows a particular intervention or to the control particular intervention or to the control group (which does not receive the particular group (which does not receive the particular treatment/intervention under investigation). treatment/intervention under investigation).

BEST EVIDENCE?BEST EVIDENCE?

• Provides best evidence for whether Provides best evidence for whether something ‘works’ or notsomething ‘works’ or not

• Evidence based – accountabilityEvidence based – accountability• Provides evidence in numerical form – Provides evidence in numerical form –

easy to give clear messages to decision-easy to give clear messages to decision-makers/practitionersmakers/practitioners

• An RCT, by design, generates highly An RCT, by design, generates highly trustworthy datatrustworthy data

• Ethical issues?Ethical issues?

TriangulationTriangulation

• First used as a metaphor, borrowed from First used as a metaphor, borrowed from navigation, to characterize the use of multiple navigation, to characterize the use of multiple methods to measure a single constructmethods to measure a single construct

• The combination of two or more theories, data The combination of two or more theories, data sources, methods or investigations in one sources, methods or investigations in one study of a single phenomenon (Denzin,1989)study of a single phenomenon (Denzin,1989)

• Adds new perspectives to the phenomenon Adds new perspectives to the phenomenon under investigation giving a richer and more under investigation giving a richer and more comprehensive picture (Foss and Ellefsen, comprehensive picture (Foss and Ellefsen, 2002)2002)

Discussion Discussion

• To what extent is generalisability To what extent is generalisability possible, or even desirable, in research ? possible, or even desirable, in research ?

• Discuss the extent to which it is possible, Discuss the extent to which it is possible, or even desirable, for a researcher to or even desirable, for a researcher to remain objective and detached from their remain objective and detached from their research.research.

• What are the ethical implications of What are the ethical implications of RCTs?RCTs?

ReferencesReferences

• Burns, N. & Grove, S.K. (1987) Burns, N. & Grove, S.K. (1987) The Practice of Nursing The Practice of Nursing ResearchResearch, W.B.Saunders, Philadelphia., W.B.Saunders, Philadelphia.

• D.E. Carter (1996) in D. Cormack (ed) D.E. Carter (1996) in D. Cormack (ed) The Research The Research Process in NursingProcess in Nursing, Blackwell, Oxford., Blackwell, Oxford.

• Denzin, N.K. (1989) Denzin, N.K. (1989) The Research Act: A Theoretical The Research Act: A Theoretical Introduction to Sociological MethodsIntroduction to Sociological Methods, 3, 3rdrd edn. McGraw- edn. McGraw-Hill, New York.Hill, New York.

• LeCompte, M.D. & Goetz, J.P. (1982) Problems of reliability LeCompte, M.D. & Goetz, J.P. (1982) Problems of reliability and validity in ethnographic research. and validity in ethnographic research. Review of Review of Educational ResearchEducational Research, 52, 31-60. , 52, 31-60.

• Foss, C. & Ellefsen, B. (2002) The value of combining Foss, C. & Ellefsen, B. (2002) The value of combining qualitative and quantitative approaches in nursing research qualitative and quantitative approaches in nursing research by means of method triangulation. by means of method triangulation. Journal of Advanced Journal of Advanced NursingNursing, 40(2), 242-248., 40(2), 242-248.