Research methods Flashcards
Quantitative research
Aim:
- nomothetic approach (derive universally applicable rules)
- these rules may be applied to the behaviour of large groups of individuals
Focus: behavioural manifestations (operationalisations)
Data: Numbers
Objectivity: more objective- the researcher is eliminated from the studied reality
Types:
- experiment
- quasi-experimental
- correlational study
Qualitative research
Aim:
- idiographic approach (in-depth understanding of a particular case or phenomenon)
- obtained knowledge isn’t a universal law, but it’s deeper in the sense that a particular case is understood more holistically
Focus: Human experiences, interpretations, meanings
Data: Texts
Objectivity: more subjective- researcher is included in the studied reality
- researcher is an integral part of the procedure and a “tool of measurement”
Types:
- observation
- interview
- focus group
- case study
Sample
a group of individuals taking part in the research study
Define sampling
process of recruiting individuals for participation
Define credibility
extent to which results of the study can be trusted to reflect the reliability
- study is credible when there are reasons to believe that its findings are true
Qualitative research study:
Credibility = trustworthiness
Quantitative research study:
Credibility = internal validity
Define bias
- characterises various distortions introduced to the findings by the researcher, research procedure, mistakes in process of measurement etc.
Define generalisability
extent to which results of the study can be applied beyond sample and setting used in the study itself
Sampling in quantitative research
Experimental studies and correlational studies
- random sampling
- stratified sampling
- self-selected sampling
- opportunity sampling
Sampling in qualitative research
- quota sampling
- purposive sampling
- theoretical sampling
- snowball sampling
- convenience sampling
Two types of quantitative research
- Experimental studies
2. Correlational studies
Generalisability in quantitative research
Experimental studies:
- External validity: ecological validity and population validity
- Construct validity
Correlational studies:
- population validity
- construct validity
Generalisability in quantitative research
- sample-to-population generalisation
- case-to-case generalisation
- theoretical generalisation
Credibility in quantitative research
Experimental studies:
- referred to as internal validity
- ways to improve this: controlling confounding variables; eliminating or keeping constant in all conditions
Correlational studies:
- referred to as credibility
- ways to improve: using reliale ways to measure the variables; avoid biases in interpreting results
Credibility in qualitative research
- referred to as credibility/trustworthiness
- ways to improve this: triangulation, establishing a rapport, iterative questioning, reflexivity, credibility checks, thick descriptions
Bias in qualitative research
Experimental studies- Threats to internal validity:
- selection, history and maturation
- testing effect and instrumentation
- regression to the mean
- experimenter mortality
- experimenter bias
- demand characteristics
Correlational studies:
- While measuring variables: depends on the method of measurement
- While interpreting findings: curvilinear relationships, third variable problem, spurious correlations
Bias in qualitative research
Participant bias:
- acquiescence
- social desirability
- dominant respondent
- sensitivity
Researcher bias:
- confirmation bias
- leading questions bias
- question order bias
- sampling bias
- biased reporting
Variable
any characteristic that is objectively registered and quantified
Construct
any theoretically defined variable eg. violence, attraction, memory, anxiety
- constructs need to be operationalised
What does it mean to operationalise a construct?
means expressing the construct in terms of observable behaviour
A good operationalisation will:
- capture the essence of the construct
- be clearly measurable
Independent variable
variable that is manipulated by the experimenter
Dependent variable
variable that changes as a result of the manipulation by the experimenter- the one that is measured
Confounding variables
other variables (other than IV and DV) that can interfere in the relationship between the IV and the DV - this is to ensure that it is the change in the IV that causes the change in the DV
Target population
the group of people to which the findings of the study are expected to be generalised
- sample: group of people that take part in the experiment; a sub-set of the target population
Target population and generalisability
- results of quantitative research need to be able to to be generalised from the sample to the target population
- for this to be possible, sample must be representative of the target population
- a sample is representative if it reflects all of the essential characteristics of the target population
Sampling techniques used in quantitative research
- Random sampling
- Stratified sampling
- Convenience (opportunity) sampling
- Self-selected sampling
Random sampling
- What it is
- Advantages
- Disadvantages
What it is:
- create a list of all members of the target population and randomly select a sub-set
- this way every member of the target population has an equal chance of being a part of the sample
Advantages:
If sample size is sufficient, researchers may be certain that even unexpected characteristics are fairly represented in the sample
Disadvantages:
It’s practically impossible to carry out truly random sampling
eg. target population may be geographically dispersed
Stratified sampling
- What it is
- Advantages
- Disadvantages
What it is:
- decide on the list of essential characteristics of the population that the sample has to reflect
- then study the distribution of these characteristics in the target population
- then recruit participants randomly, but in a way that keeps the same proportions in the sample as observed in target population
Advantages:
- allows researchers to control representativeness of some key characteristics without relying on chance
- useful when: researcher is certain about which characteristics are essential; sample sizes aren’t large
Disadvantages:
- requires more knowledge about the characteristics of the target population
- harder to implement
Convenience (opportunity) sampling
- What it is
- Advantages
- Disadvantages
What it is:
- recruiting participants that are easily available
Advantages:
- useful when financial sources are limited
- in some studies, there may be a reason to believe that people aren’t that different
- useful when the generalisation of findings isn’t the primary purpose of the study
Disadvantages:
- generalisation is very limited due to sampling bias
Self-selected sampling
- What it is
- Advantages
- Disadvantages
What it is:
- recruiting volunteers
- anyone that wants to participate is included in the sample
Advantages:
- a quick and easy method to recruit participants
- at the same time has wide coverage
Disadvantages:
- representativeness and generalisation are limited
- a typical volunteer is more motivated than the average participant from a bigger population
- volunteers could pursue monetary incentives for their participation
3 types of experimental design
- based on how the independent variable is manipulated
- Independent measures
- Matched pairs
- Repeated measures
Independent measures design
- advantages
- disadvantages
- how to overcome the disadvantages
- IV is manipulated by randomly allocating participants into different groups
- rationale behind random group allocation: all potential confounding variables cancel each other out
Advantages:
- can have multiple groups
- participants only take part in one condition, so no order effect and more difficult for them to figure out true aim of the study
Disadvantages:
- participant variability: different people are used, likely that participants in the groups won’t be completely equivalent at the start of the study
How to overcome the disadvantages:
- when allocation into groups is random and groups are large enough, it’s likely that pre-existing individual differences will cancel each other out and groups on average will be equivalent
Matched pairs design
- advantages
- disadvantages
- how to overcome the disadvantages
- researchers use matching to allocate participants into different groups
- participants are assessed on a matching variable
- all participants are ranked according to the matching variable and allocated randomly into groups pairwise as we move along the ranks
- the participant then allocates each pair randomly into groups, until all participants have been allocated
- this way researcher ensures that the two groups are equivalent in terms of this one variable, and all other characteristics are kept random
Advantages:
- useful when researcher is particularly careful about certain confounding variables and wants to keep them constant in all groups
- useful when sample size isn’t large and there’s a chance that random allocation will end up producing groups that aren’t equivalent
Disadvantages:
- more difficult to implement because matching variables need to be measured first
- theory-driven: researcher needs to know what variables are likely to be confounding
How to overcome disadvantages:
- keeping the experiment simple
- matching is easier to implement when there’s one matching variable and 2 groups
Repeated measures design
- advantages
- disadvantages
- how to overcome the disadvantages
- same group of participants is exposed to 2 (or more) conditions and the conditions are compared
- this way participants are compared to themselves (also called “within-subject” designs)
Advantages:
- participant variability isn’t a problem as participants are compared to themselves
- means that sample sizes can be smaller
Disadvantages:
- order effects: fatigue or practice
- participants take part in more than one condition, increases the chances that they’ll figure out the true aim of the study
How to overcome the disadvantages:
- counterbalancing
- however, this is difficult when there are many conditions
How is the quality of experiments determined?
Quality of an experiment is characterised by its:
- construct: characterises generalisability of results
- internal validity: credibility of the experiment
- external validity: characterises generalisability of results
Construct validity
a characteristic of the quality of operationalisations
- operationalisations express constructs in terms of observable behaviour
- is high if operationalisation provides sufficient coverage in the construct
- relates to the overarching concept of generalisability; it characterises generalisability of findings to the theory
External validity
- a characteristic of generalisability of findings to other people and other situations
Two types:
- population validity
- ecological validity
Population validity
- the extent to which findings can be generalised from the sample to the target population
- it depends on how representative the sample is
Ecological validity
- the extent to which the findings can be generalised from the experiment to other settings or situations
- depends on how artificial the experimental procedure is
Lab experiments:
- participants find themselves in situations that don’t normally occur in their daily lives
- this can change their behaviour, making it less natural
The more closely the experimental procedure approximates real-life situations, higher the ecological validity of the experiment
Internal validity
- a characteristic of the methodological quality of an experiment
- it relates to credibility of the research study
- it’s high when confounding variables have been controlled and are certain that it was the change in the IV that caused the change in the DV
- it links directly to bias
- the less bias there is, higher the internal validity of teh experiment
Internal validity and ecological validity
Usually there is an inverse relationship between internal validity and ecological validity
- when internal validity is high, ecological validity is low
- when ecological validity is high, internal validity is low
Threats to internal validity (RED TIME)
- Regression to the mean
- becomes a threat when initial score on DV is extreme (v. low or v. high)
- Counteracted: a control group w/ same starting score on the DV, but no experimental manipulation - Experimental mortality
- occurs when some participants drop out of the experiment; is only a problem when rate of dropping out isn’t the same in every experimental condition
- Counteracted: Design experimental condition so participants don’t feel discomfort causing them to withdraw - Demand characteristics
- occurs when participants understand true aim of the experiment and alter their behaviour (unintentional/ intentional) as a result
- a bigger problem in repeated measures design as participants take part in more than one condition
- Counteracted: deception to conceal true aim of the study (but ethical considerations arise); post-experimental questionnaires to investigate extent to which participants could guess true aim of the study - Testing effect
- first measurement of DV may affect subsequent measurements; sometimes in independent measures, DV is measured twice eg. before and after experiment
- in repeated measures designs testing effect is a special case of order effects
- Counteracted: in independent measures designs there must be a control group, the same test and retest, but no experimental manipulation; in repeated measures, counterbalancing must be used - Instrumentation
- occurs when instrument measuring DV changes slightly between measurements, compromising standardisation of measurement process
- Counteracted: standardise measurement conditions as much as possible across all comparison groups and all observers - Maturation
- natural changes that participants go through in the course of the experiment eg. fatigue or growth (if procedure is extended in time)
- Counteracted: have a control group; if we can assume that rates of maturation are the same in both groups, comparison won’t be affected - Experimenter bias
- occurs when researcher unintentionally influences participants behaviour and results of the study
- Counteracted: use a double-blind design; neither participants nor experimenter knows who has been assigned to what condition
What are the different types of experiments?
- True experiment
- Quasi-experiment
- Laboratory experiment
- Field experiment
- Natural experiment