Qualitative Vs Quantitative


Yet another psychological debate with endless theories from either side. Nature Vs Nurture, Reductionism Vs Holism to name a couple, are joined by Qualitative Vs Quantitative in the major debates that we as psychologists are forced to ponder over till are heads hurt. I could name the pros and cons of each of the measures, but since this is such a repetitive argument, let’s get right down to the crux of the argument, the cons.

The main problem with qualitative measure that they are open to the investigators interpretation. Take for example if we were observing depressed behaviours within patients in semi-structured interviews. How do we actually define a construct such as depression? Sure, there may be guidelines and definitions to make diagnosis easier, but at the end of the day it’s up to the investigator or clinician in question to decide what are depressive behaviours. Even with inter-rater reliability (the whole point of these guidelines) behaviour will always be open for interpretation. This idea is supported by the work of Perez-Stable: ( http://archinte.ama-assn.org/cgi/content/abstract/150/5/1083 ) this study shows just a representation of the mis-diagnosis of depression within a clinical setting. Throw in other behavioural traits such as anxiety and obsession and were already encountering numerous reliability problems just based on diagnosis, let alone whether the patient is truthfully responding to conditions.


Well on the flip side we could use quantitative research method to try and find an un-bias measure of depression. Take the GDS developed by Sheikh and Yesavage: (http://psycnet.apa.org/psycinfo/1988-34658-001) a scale devised to identify depression within elderly patients. This scale would be admitted via self report measures where the patients would rate themselves on the scale. This in then turn would produce lots of quantitative results which could be analysed via t-tests and several measures of reliability, while at the same time reducing interpretation effects. Sounds amazing doesn’t it? There’s always two sides to every story and truth be told, quantitative measures are no exception. The problem with scales filled out by participants and patients is that they are able to show biases of their own, for example desirability bias. Participants will rate themselves how they see will be seen correct, beneficial, or “normal”. This effect is demonstrated by the work of Adams et al. (http://aje.oxfordjournals.org/content/161/4/389.short)  Although this research is talking about desirability in amount of exercise, the effect can be generalised to desirability of depression and other conditions. Another problem with these self-report measures are leading questions: “how depressed would you rate yourself” for example. Even if the scale was from “not at all” to “very,” there’s an automatic assumption of depression within the participant. This may cause positive desirability in a lower than actual depression score, or negative desirability by over-rating how depressed they are.

I think the important thing to take note, is that regardless of many different perspectives of research there are, theories, or even ideas of human behaviour, there are always going to be infinite ideas of how to measure or support these ideas. With both quantitative and qualitative measures, there are most definitely faults, but if we combine both of them then we can eliminate or balance certain biases to some extent, and analyse our research to greater effect. Make the whole experiment and research more scientific, and isn’t that the point of psychology? Determine human behaviour in a scientific way? If we as psychologists can at least agree that both these types of measures have their place in research, then surely were half way there?



5 thoughts on “Qualitative Vs Quantitative

  1. I think the main problem, and the reason why this is such a big debate, is whether psychology can really be considered a science if it uses qualitative methods. There not objective for starters, quite hard to re-test ans its often down to individual interpretation and thus bias is so easily applicable to qualitative research. But as you said these methods can often be quantified. They can also be extreamly useful in finding a research question to begin with.

    I thought it was intresting how you took the topic of depression though and examined the different ways of testing it. I think you could have expanded on this so much, it was quite intersting, maybe food for thought for your next blog 🙂

  2. Pingback: Homework – Week 8/9 « laf1993

  3. I like your idea about qualititive methods being very subjective, especially since the dsm is constantly being revised as the definitions change because there is still lots of debate about which symptoms develop and are shown when and in which ways, e.g. the removal of hysteria from the dsm.

  4. Hi, i think that there is always going to be debates in psychology like this because too many people like one thing over another or specialise and are sooooo passionate about certain areas in the subject. And as you have so brilliantly shown there are obviously pros and cons to both arguments but i think it just comes down to the context and which one would be best for the job. lots of opinion cannot easily be measured with numbers for example and how we feel is always going to be analysed in further depth by words in my opinion – yes you can use scales but all the categorising doesnt really go into sufficient detail for some things.
    I also found these articles that show how mixed methods can be used and try to mix both qualitative and quantitive methods… crazy i know 🙂

  5. I completely agree. Psychologist argue over which is better and slag of the opposite one they use. Surely no psychologist should slag off another psychologists work, we are meant to come together and support each other and back psychology as a good, reliable, valid and scientific area. Here, a researcher expresses the problems in qualitative research (http://ukpmc.ac.uk/abstract/MED/8311428/reload=0;jsessionid=CBF016BA68C9EA15A329E83028A680AA). We should except that different research requires different methods and it would be unscientific to use the other method on the other research.

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