Quantitative research by RichardRodriguez66

VIEWS: 0 PAGES: 21

									                Research Approaches 2:
                 Quantitative research
                       How many versus how well

                              Ian Grigor

School of Healthcare
                       Aim
      To understand the role of 
       quantitative research




School of Healthcare
                       Objectives
      l   To understand the principle of 
          research methods adopting a 
          quantitative approach (basically 
          involving experimental design)
      l   To interpret the role of quantitative 
          research
      l   To comment on the strengths and 
          weaknesses of quantitative research

School of Healthcare
                        What is research?
    The generation of information              (perhaps)            New concepts
    and understanding                          consisting of        New models
                         as opposed to                              New theories


                       unsupported            So we need            evidence
                       opinion
                                                                      as opposed to

                                                                     anecdote

        validity                           Determinants are

                             reliability

                                                 generalisability
School of Healthcare
     Quantitative research traditions

      l   Focus predominantly (though not 
          exclusively) on experimental design. A 
          good example might be a survey 
          questionnaire
      l   Experimental design has long been 
          perceived as the gold standard for 
          medically-orientated research
      l   Rely largely on statistical measures and 
          require larger samples and more 
          structured data collection tools (Polit et al 
          2001)

School of Healthcare
  Why and when do we prefer to
   talk in quantitative terms?

      l   We like to quantify “things” because 
          we have an awareness of scales
      l   There’s an element of “value” 
          attached to a quantity
      l   When we’re “being professional”
      l   When it’s necessary to get a message 
          across

School of Healthcare
                 What is quantitative
                     research?
      Burns & Grove (1987)
      “... a formal, objective, systematic
        process in which numerical data are
        utilized to obtain information about
        the world" and "a research method
        which is used to describe and test
        relationships and to examine cause-
        and-effect relationships".
School of Healthcare
      Elements of quantitative
             research
      l   Tests and experiments under 
          controlled conditions
      l   Cause and effect relationships 
          (Alderson 1998)
      l   Gathering numerical data objectively
      l   Results lend themselves to statistical 
          analyses
      l   Evaluation of results confirm or 
          refute the original hypothesis
School of Healthcare
Elements of quantitative research can be
  described as positivist paradigms…

      l   Quantitative data
      l   Statistical analysis within definitive 
          concepts (logical mathematics)
      l   Atomistic (focusing on component parts)
      l   Studying discrete relationships
      l   Being of low complexity???
      l   Potentially seeking to explain laws
      l   Requiring control subjects/sets
      l   Ultimately, we should understand what we 
          don’t know at present!! 

School of Healthcare
                       Samples for study

      Your “sample” is the group of cases (people, 
        organisations, etc.) that you study in your 
        research
      l It should be either comprehensive i.e. 
        everyone or a selection that is truly 
        randomised, inclusive and controlled
      l It should not be a limited study of 12 (cf 
        Wakefield et al 1994: 1998: 2001) unless 
        that is all that is in the population under 
        scrutiny

School of Healthcare
                       In relation to our ongoing
                             MMR theme…
      Studies by Gillberg & Heijbel (1998); Honda (2005); 
        Peltola et al (1998); Taylor et al (1999) 
        quantified the number of doses of MMR given 
        over a period of time in a specific country or area 
        and also quantified the number of cases of 
        autism diagnosed in the population given the 
        MMR vaccine. Then, using statistical testing to 
        determine whether there was any evidence of an 
        association between these variables (MMR and 
        autism), they tried to ascertain the strength of the 
        association: this is quantitative research


School of Healthcare
  Using Wakefield’s work on the
  MMR debate as our metaphor…

      l   The information and understanding 
          generated was highly questionable
      l   His opinions have been heavily criticised
      l   His claims were based on a study of 12 
          children
      l   A Scandinavian study of 300,000 came to 
          the opposite conclusion
      l   Any comments about 
          generalisability?

School of Healthcare
   Validity of data generation

      l   Do your data relate to the concepts you 
          think they do?
      l   What steps were taken to tackle these 
          issues? Convince the reader that you’ve 
          thought about this and confront the issue
      l   Are your data appropriate?
           » Is the combination of methodology and the 
             cases under study able to generate the data 
             required for the study?
           » Could there be extrinsic factors influencing 
             your results?


School of Healthcare
                         Validity

      l   Are hidden factors at play?
           » You think you’re looking at the effects of 
             X but other factors you’re unaware of 
             are really what are affecting the situation
      l   Your explanation applies to much of 
          your data even though you sought 
          negative instances/ alternatives


School of Healthcare
                       Reliability

      l   Could another researcher repeat this 
          work, using the same data, and end 
          with the same result?
      l   Have you consistently used 
          standardised protocols and 
          techniques?



School of Healthcare
                       Generalisability

      l   Could your findings be 
          applied to the wider 
          population?
      l   If not, why not?
      l   Can we make predictions 
          from our study sample to the 
          general?

School of Healthcare
              Strengths of quantitative
                      research
       l   You can manipulate your numbers to 
           create visual images e.g. graphs
       l   Concepts can be “measured” and directly 
           compared to previous/subsequent work
       l   There may be direct correlation between 
           cause and effect – this is the ideal
       l   It may be possible to generalise towards 
           external validity i.e. predict
       l   Breadth of coverage of big population

School of Healthcare
      Weaknesses of quantitative
              research
      l   The whole may not be equal to the 
          sum of the parts
      l   Lack of depth i.e. looking at just one 
          part of the whole
      l   Defining everything, in terms of 
          numbers, is risky when dealing with 
          humans especially 
      l   Ultimately, everything is qualitative!

School of Healthcare
    The final evidence on the MMR
             controversy…

      “The evidence is that MMR is not associated
        with autism in children…the quality,
        validity and size of that evidence is
        overwhelming…autism rates began to rise
        before MMR…”
      Anon (2005) MMR vaccination and autism 
        Available at www.ebandolier.com 
      The worldwide studies on this topic have 
        covered some 2 million people

School of Healthcare
                       References

      l Alderson P (1998) The importance of 
        theories in health care British Medical
        Journal 317, 1007-10
      l Hek G, Judd M and Moule P (2002) 
      Making sense of research: an
        introduction for health and social
        care practitioners (2nd edition)
      London: Continuum

School of Healthcare
                       Objectives

      l   To understand the principle of 
          research methods adopting a 
          quantitative approach 
      l   To interpret the role of quantitative 
          research
      l   To comment on the strengths and 
          weaknesses of quantitative research

School of Healthcare

								
To top