A nurses' guide to Quantitative Research

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A nurses’ guide to Quantitative Research

AUTHOR

Rebecca (Becky) Ingham‑Broomeld

RN (NSW); CertEd; DipNurs (London); BSc (Hons);

MSc (Health Psychology)

Lecturer in Nursing, University of New England, Armidale,

NSW, Australia.

[email protected]

KEY WORDS

research methodology, Quantitative research, evidence based practice (EBP).

ABSTRACT

Objective

This article provides a breakdown of the components of quantitative research methodology. Its intention is to

simplify the terminology and process of quantitative research to enable novice readers of research to better

understand the concepts involved (Benner 1984).

Primary Argument

Globally, evidence‑based practice (EBP) has become a major preoccupation of investigators and practitioners

involved in the delivery of health care (Liamputtong 2013 pxxi). Working within the health sector requires the nurse

to be familiar with research in a way that informs practice, especially if working towards a degree (**Wright‑St Clair

etal2014).Nursesmaybenetfromadiscussionthathelpsthemunderstandthesequenceofaresearchpaper

(Moxham 2012) that uses quantitative methodology.

Conclusion

The content of a typical quantitative research paper will be discussed in a systematic, logical order. A quantitative

grid is provided at the end of the paper. Its intention is to aid the nurse to better understand the differing

components of the four main quantitative research methods.

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INTRODUCTION

There is an increased emphasisonEBPtosubstantiate clinical decision-making. EBP is dened as the

conscientious integration of best research evidence with clinical expertise, patient values and needs in

the delivery of high‑quality, cost effective health care (**Wright‑St Clair et al 2014; Burns and Grove 2009

p17). Health clinicians use tools, such as pain or depression scales, frequently in clinical practice and during

research (Imms and Greaves 2013). In this paper only quantitative research will be discussed as one paradigm

for researching health.

THE QUANTITATIVE RESEARCH PAPER

Denition and meaning of Quantitative research

Quantitative research is a means for testing objective theories by examining the relationship among variables

(Polit and Hungler 2013; Moxham 2012). A variable is a factor that can be controlled or changed in an

experiment (Wong 2014 p125). The word quantitative implies quantity or amounts. Information collected

inthecourseofthestudyisinaquantiedornumericform(WhiteandMillar2014).Thisisreferredtoas

statistical evidence (White and Millar 2014).

The variables include the Dependent variable (the variable which is hypothesised to depend on or be caused

byanothervariable)orIndependentvariable(thevariablethatisbelievedtobethecauseorinuence)(Wong

2014; Polit and Hungler 2013). There may also be Extraneous variables (Polit and Hungler 2013), also known

as Confounding variables (White and Millar 2014 p47), which confuse or confound the relationship between

the Dependent and Independent variables. An example would be as follows: wound healing (Dependent

variable) and type of dressing (Independent variable). Patient age and presence of Diabetes Mellitus would

be Extraneous/Confounding variables.

Quantitative research falls within the philosophical underpinning of Positivism. A Positivist researcher believes

in the concepts of objective reality (Jirojwong et al 2014 p362). Quantitative research attempts to establish

statisticallysignicantrelationships,addressesquestionsbymeasuringanddescribing,isbasedonobjective

measurement and observation, and is concerned with correlation and causation (Hamer and Collinson 2014).

Aspecicexampleofpositivismiswherethereisgenerallyconsensualagreementonfoundationalaspects

of human body structures (*Wright‑St Clair 2014 p18).

Abstract/Summary

An abstract or summary should clearly outline the hypothesis or research question/s, aims and objectives of

the study (Polit and Hungler 2013; Nieswiadomy 2012). A hypothesis is a statement of a predicted relationship

between the variables under study (Polit and Hungler 2013). The research may state a Null hypothesis which

predicts no relationship between the variables (White and Millar 2014 p43; **Wright‑St Clair et al 2014,

p.456). It should also cite the quantitative methods used to collect the data, the results, conclusions and

recommendations for practice (Nieswiadomy 2012). Abstract length is generally less than 200 words (Borbasi

and Jackson 2012 p178). The abstract may also include some of the limitations of the study.

Identifying the problem

The problem should clearly describe what is to be studied. The hypothesis, aims and/or objectives should be

clearlyandunambiguouslystated.Ideallythetopicisnarroweddowntoaspeciconesentencestatement

of the problem (Nieswiadomy 2012). A useful strategy for formulating EBP question is the acronym PICO/s

(patient, population or problem, intervention or interest, comparison, outcome and study design) (Hoffmann

et al 2013 p22; **Wright‑St Clair et al 2014 p457; Burns and Grove 2009 p474). Ideally four criteria are

usedinquantitativeresearchnamelysignicance,researchability,feasibilityandinteresttotheinvestigator

(Moxham 2012 p33).

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Literature Search

The literature review is generally in the introductory section (Polit and Hungler 2013). The investigator needs

to determine what is known and not known about the problem, identify gaps in knowledge, establish the

signicanceofthestudyandsituatethestudywithinthecurrentbodyofknowledge(Hoffmannetal2013;

Polit and Hungler 2013; Burns and Grove 2009). The literature search should consider how the major variables

were explored by critiquing the strengths and limitations of the methods previously used. The investigator

may also acquire information about other techniques, instruments and methods of data analysis as well as

also identify potential problems that can be avoided in a new research (Polit and Hungler 2013).

METHODOLOGY

Designs

Quantitative research falls into four main designs, namely, Descriptive, Correlational, Experimental and Quasi‑

experimental (Borbasi and Jackson 2012; Burns and Grove 2009). The main aim of Descriptive Research

is the accurate portrayal of the characteristics of individuals, situations, or groups and the frequency with

which certain phenomena occur using statistics to describe and summarise the data (Polit and Hungler

2013). Correlational research explores the interrelationship amongst variables of interest without any active

intervention on the part of the researcher (Polit and Hungler 2013). Experimental research is systematic and

objective, particularly in medication trials, known as a Random Controlled Trials or RCT’s. They are considered

asthe‘goldstandard’inresearchevidence(HamerandCollinson2014p19).InExperimentalresearchthe

investigator controls the independent variable and randomly assigns subjects to different conditions. Quasi‑

experimental research is less powerful than Experimental due to the lower level of control (Burns and Grove

2009). The investigator manipulates an independent variable but subjects cannot be randomised (Polit

and Hungler 2013). The choice of design should allow the variable to be measured or manipulated in the

study(BurnsandGrove2009).Beforeastudycanprogress,theinvestigatorwillusuallyclarifyanddene

the variables under investigation and specify how the variable will be observed and measured in the actual

researchsituation(PolitandHungler2013).Thisisknownasanoperationaldenition(PolitandHungler

2013; Nieswiadomy 2012). These four designs, discussed above, are compared in the grid at the end of this

paper to highlight similarities and differences in style.

Instrument

Quantitative instruments may include self‑reporting tools, questionnaires, observation, and biophysical

measures (Polit and Hungler 2013). Commonly used methods in nursing research also include focus groups

and interviews that are qualitative in nature (Moxham 2012). Using both styles is referred to as mixed or

multi-methodresearch(PolitandHungler2013).Scalesmaybeusedtoquantifyspecicinformationsuchas

aLikertscalegivesspecicchoicesforexample,stronglyagree,agree,notsure,disagree,stronglydisagree

(Polit and Hungler 2013). Whatever instrument is used the reliability and validity of the instrument is essential.

Reliability refers to the degree of consistency or accuracy with which an instrument measures the attribute

it has been designed to measure (Polit and Hungler 2013). Data retrieved may look authoritative but it could

beincompleteorinaccurateormaynotbesufcientlyreliabletobeofvalueingeneralisingtothelarger

population. Concurrently, validity refers to the degree to which the instrument measures the phenomena in

therstplaceorreectstheabstractconstructbeingexamined(BurnsandGrove2009p479).

Sample

Descriptive research may use probability sampling which includes simple random, stratied sampling,

proportionate stratied sampling and cluster sampling (Shaughnessy et al 2014). Random sampling is

also known as probability sampling, rather than non‑probability sampling, which ensures every element is

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likely to be included in the sample (Shaughnessy et al 2014). Correlational and Experimental research use

random sampling. Random sampling gives every member of a population an equal chance/probability of

beingincluded(PolitandHungler2013).Quasi-experimentalresearchiscalled‘quasi’becauseitispart,or

almost, experimental. The component that makes it quasi is the use of a convenience or accidental sample

which does not give the population equal probability of being included and therefore, less rigorous in design

(Polit and Hungler 2013).

Ethics

The investigator is obliged to consider the implications of the proposed research for the participating subjects,

their families and society (Burns and Grove 2009). Most nursing research usually requires the permission of an

appropriate ethics committee (Elliott et al 2012 p93; Jirojwong et al 2011 pp63‑66). Ethical guidelines outline

a set of standards for conducting research. Within their practice nurses have a moral and legal obligation to

protect the privacy of an individual (Nursing and Midwifery Board of Australia 2012, Conduct Statement 5)

and this holds true within nursing research. Equally important is the premise to protect individuals from the

riskofsignicantharm(NursingandMidwiferyBoardofAustralia2012,ConductStatement8).Itisimportant

that consent is obtained after full explanation of the study’s intent (Borbasi and Jackson, 2012). Participants

are entitled to withdraw from the study at any point without penalty (Jirojwong et al 2014 p70).

Pilot Study

A pilot study is a trial run of the research (Nieswiadomy 2012). It is conducted on a small number of participants

to assess the adequacy and feasibility of the intended research (Moxham 2012 p35). By doing so the pilot

study can identify problems and strengthen the quantitative methodology.

Main Study

Theresearchprocessdependsonthecollectionofdataknownmorespecicallyasempiricaldata(Moxham

2012p35)whichisrootedinobjectivityorascienticapproach(PolitandHungler2013).Itisatthispoint

that the researcher puts the design into action and ensures that the data is collected and recorded. The

ndingsneedtobeanalysed,andinthecaseofquantitativeresearch,statisticalanalysisandinterpretation

is an essential part of answering the hypothesis or research questions (Borbasi and Jackson 2012 p114).

Results

Data analysis may involve descriptive or inferential statistics (Moxham 2012). Descriptive statistics describe

and synthesise data and show patterns and trends (Moxham 2012) whereas inferential statistics permit the

investigator to infer whether relationships noted in a sample might occur in a larger population (Polit and

Hungler2013).Numericaldatamaybepresentedintwoforms,rstlyasrawguresandpercentagesand

secondly, more visually, as line graphs, tables or histograms (Burns and Grove 2009). To analyse variables

statistically they have to be in a measurable form that means using numbers or scores (Borbasi and Jackson

2012).

Measures of central tendency, known as the average, identify how near the usual response a particular

variable lies (Burns and Grove 2009). These averages are expressed as mean, median and mode (Burns and

Grove 2009). The mean is the average, for example, all scores are added up and divided by the number of

subjects. The median represents the exact middle score or value in a distribution of scores. The mode is the

value that occurs most frequently in a distribution of scores (Polit and Hungler 2013; Burns and Grove 2009).

Probability refers to the likelihood of a particular outcome (White and Millar 2014 p43). Statisticians use

p-valuestomeasureprobability(WhiteandMillar2014p43).Asimpleexampleofprobabilityisippingacoin

tentimes.Itwillmostlikelyfallvetimesasheadsandvetimesastails.Todetermineasignicantresult

thestatisticshavetohavelevelsofsignicance.Figuresmaybeexpressedasp>0.05orp<0.05(Burnsand

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Grove2009p37).Ifaprobabilityresultisstatisticallysignicant(p=<0.05)theresulthadalessthan5%

possibilityofbeingcausedbychanceandthereforebecomessignicantandimportant(PolitandHungler

2013).Evenwhenaresultisclaimedtobestatisticallysignicantitisimportanttoremembertheresults

may still tell us nothing that matters whilst relationships that do not achieve conventional levels of statistical

signicancecanbeimportant(Lempert2008).

AnothertermusedinquantitativeresearchistheCondenceInterval(CI).Wheneverameaniscalculated

using a sample there is always the possibility of error. The investigator will calculate the CI. If they arrive at a

CIof95%itmeansthattheinvestigatorissatisedthat95%ofthetruepopulationliesbetweentwovalues

(Liamputtong2013p413)forexample,theinvestigatormayndaverageheightofhumansfallsbetween

1.4m and 1.8m. Essentially the CI represents how true the estimate is (Hoffmann et al 2013 p80). A CI is

an important reminder regarding the limitations of estimates. The greater the sample size the more precise

the CI (Liamputtong 2013 p297).

Standard Deviation (SD) is the spread of data from a mean value (White and Millar 2014 p41). Using the

example of human height, if normal standard height falls between 1.4m and 1.8m then heights outside

those ranges deviate from the norm. The mean and standard deviation are two statistics that help determine

differences and similarities in groups that are being researched (White and Millar 2014 p41).

Discussion/Recommendations

Thediscussionofndingsallowstheinvestigatorstomakeinterpretations(Nieswiadomy2012)thatneed

to be analysed in an objective and critical manner before drawing conclusions. Recommendations could be

implemented in practice readily or cautiously taken up and piloted over a period of time. Alternatively the

resultsmaynotbeconsideredunlessmodicationsaremade.Animportantpointtorememberisthatthe

research does not necessarily prove a point and may only suggest a relationship or highlight an issue needing

further investigation. A body of evidence, to support clinical practice, particularly in RCT’s, is the most reliable

source of evidence (Borbasi and Jackson 2012 p195). Limitations of the research should be acknowledged.

Conclusions

Allmajorndingsrelatedtotheoriginalaimsofthestudyarediscussedinrelationtowhetherthedata

supports or negates the hypothesis or research question/s (Nieswiadomy 2012).

Reference List

Research papers conclude with a list including books, reports and other journal articles used to support the

concepts outlined. For those interested in pursuing additional reading on the topic, the reference list provides

an excellent starting place (Polit and Hungler 2013).

ARTICLE CONCLUSION

This paper has discussed quantitative research logically and systematically. Whilst this paper is deliberately

simplieditstillallowsforthemaincomponentsofthequantitativeresearchprocesstobeidentiedforthe

novice researcher in nursing (Benner 1984).

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The Grid: An overview of the four styles of Quantitative Research

Content Descriptive Correlational Experimental Quasi‑experimental

Sample Simple random,

StratiedSampling,

Proportionate

StratiedSampling

and Cluster Sampling

Random Random Convenience or

accidental

Example

of types of

instruments/

tools used

Can use both

quantitative

and qualitative

methods. Relies on

instrumentation to

measure and observe.

May use microscopes,

computer models,

survey method, as

well as observational

and measurement

tools. Others may

include case studies

and archival research

projects.

Survey method may

be used to determine

correlations, for

example, when wattle

owersinSpring

more people buy

antihistamines. This

type of research may

be purely based on

observation (also known

as naturalistic research)

where subjects are

observed in their habitat

looking for behavioural

correlations.

A RCT is purely

quantitative and a

good example where

one group is the

experimental group (for

example, consented

patients receiving

new drug) and one

group which is random

(patients receiving either

an old tested drug or

placebo). Post‑test only.

Pre and post testing

knowledge and skills

using observation and

questionnaire

Ethics

permission

Essential Essential Essential Essential

REFERENCES

Benner, P. 1984. Benner’s Stages of Clinical Competence. Retrieved from http://www.health.nsw.gov.au/nursing/projects/Documents/

novice‑expert‑benner.pdf (accessed 29.10.2014).

Borbasi, S. and Jackson, D. 2012. Navigating the Maze of Research. Chatswood, Sydney: Mosby Elsevier.

Burns, N. and Grove, S.K. 2009. The Practice of Nursing Research: Appraisal, Synthesis and Generation of Evidence. Maryland Heights,

Missouri: Saunders Elsevier.

Elliott, D., Aitken, L. and Chaboyer, W. 2012. ACCCN’s Critical Care Nursing. Chatswood, Sydney: Mosby Elsevier.

Hamer, S. and Collinson, G. 2014. Achieving Evidence‑Based Practice ‑ A Handbook for Practice. Retrieved from http://bookdirectory.

net/?p=312122(accessed25.11.14).

Hoffmann, T., Bennett, S. and Del Mar, C. 2013. Evidence‑Based Practice across the Health Professions. Chatswood, Sydney: Churchill

Livingstone, Elsevier.

Imms, C. and Greaves, S. 2013. Measure Twice, Cut Once: Understanding the Reliability and Validity of the Clinical Measurement Tools

used in Health Research. In P. Liamputtong (ed), Research methods in Health. South Melbourne: Oxford University press.

Jirojwong, S., Johnson, M. and Welch, A. 2014. Research Methods in Nursing and Midwifery (2nd Edition). Sydney: Oxford University Press.

Lempert,R.O.2008.TheSignicanceofStatisticalSignicance:TwoAuthorsRestateAnIncontrovertibleCaution.WhyaBook?Retrieved

from http://repository.law.umich.edu/law_econ_archive/art86 (accessed 25/11/14).

Liamputtong, P. 2013. Research Methods in Health. South Melbourne: Oxford University Press.

Moxham, L. 2012. Nurse Education, Research and Evidence‑Based Practice. In A. Berman, S. J. Snyder, T. Levett‑Jones, M. Hales, N.

Harvey, Y. Luxford, L. Moxham, T. Park, B. Parker, K. Reid‑Searl and D. Stanley (Eds.), Kozier and Erb’s Fundamentals of Nursing (2nd

ed., Vol. 1). Frenchs Forest, Sydney: Pearson Australia.

Nieswiadomy, R.M. 2012. Foundations of Nursing Research. Boston: Pearson.

Nursing and Midwifery Board of Australia. 2012. Code of Professional Conduct for Nurses in Australia. Retrieved from http://www.

nursingmidwiferyboard.gov.au (accessed 25/11/14).

Polit, D.F. and Hungler, B.P. 2013. Essentials of Nursing Research: Methods, Appraisal, and Utilization (8th Edition ed.). Philadelphia:

Wolters Kluwer/Lippincott Williams and Wilkins

Shaughnessy, J.J., Zechmeister, E.B. and Zechmeister, J.S. 2014. Research Methods in Psychology. Online Retrieved from http://www.

mhhe.com/socscience/psychology/shaugh/index.html (accessed 25/11/14)

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SCHOLARLY PAPER

White, L. and Millar, R.B. 2014. Quantitative Approaches. In V. Wright‑St Clair, D. Reid, S. Shaw and J. Ramsbotham (Eds.), Evidence‑

based Health Practice. South Melbourne: Oxford University Press.

Wong, G. 2014. Research Questions. In V. Wright‑St Clair, D. Reid, S. Shaw and J. Ramsbotham (Eds.), Evidence‑based Health Practice.

South Melbourne: Oxford University Press.

*Wright‑St Clair, V., Reid, D. and Shaw, S. 2014. What, Why and How of Research. In V. Wright‑St Clair, D. Reid, S. Shaw and J. Ramsbotham

(Eds.), Evidence‑based Health Practice. South Melbourne: Oxford University Press.

**Wright‑St Clair, V., Reid, D., Shaw, S. and Ramsbotham, J. 2014. Evidence‑based Health Practice. South Melbourne: Oxford University

Press.