Research Methods Flashcards
Aim
A general statement of what the researcher intends to investigate.
Hypothesis
Statement of what researcher believes to be true relating to a study. Hypothesis should be operationalised.
Operationalised
Clearly defined and measurable.
Directional Hypothesis
States whether changes are greater or lesser, positive or negative.
Non-directional Hypothesis
Doesn’t state the direction, just that there is a difference, correlation or association.
Extraneous Variables
‘Nuisance’ variables that do not vary systematically with the independent variable. May have an effect on the dependent variable if it’s not controlled.
Independent Variable
Some aspect of the experimental situation that is manipulated by the researcher - or changes naturally - so the effect on the DV can be measured.
Dependent Variable
The variable that is measured by the researcher. Any effect on the DV should be caused by the change in the IV.
Demand characteristics
Any cue from the researcher or research situation that may reveal the aim of the study. This may lead to a participant changing their behaviour in the research situation.
Investigator Effects
Any effect of the investigator’s behaviour on the outcome of the research (the DV). May include everything from the design of the study to selection of, and interaction with, participants during research process.
Randomisation
The use of chance when designing investigations to control for the effects of bias.
Standardisation
Using exactly the same formalised procedures for all participants in a research study.
Control groups
Used for the purpose of setting a comparison. They act as a baseline and help establish causation.
Single blind
A participant doesn’t know the aims of the study so that demand characteristics are reduced.
Double blind
Both participant and researcher are unaware of the aims of the study to reduce demand characteristics and investigator effects.
Independent groups
One group do condition A, another group do condition B. Participants should be randomly allocated to experimental groups.
Outline the strengths of independent groups
- No order effects - participants are only tested once so can’t practise or become bored/ tired as easily. This controls CVs.
- Less likely to guess the aim - only tested once, behaviour may be more ‘natural’ as a result.
Outline the weaknesses of independent groups
- Participant variables - the participants in the two groups are different. May reduce the validity of the study.
- More participants - need twice as many participants as repeated measures for same data. More time spent recruiting which is expensive.
Participant Variables
May act as confounding Variables in an independent groups design because people in each condition are different. This may be the cause of the change in the DV rather than the manipulation of the IV.
Order Effects
Occur when participants are tested more than once (repeated measures). This might lead to a better performance through practice or worse performance due to boredom or fatigue.
Repeated Measures
Same participants take part in all conditions of an experiment.
The order of conditions should be counterbalanced to avoid order effects.
Outline the strengths of repeated measures
Avoids participant variables - people have to take part in both conditions so they have the same characteristics. Controls the CVs.
Fewer participants - less time spend recruiting participants, less expensive.
Outline the limitations of repeated measures
Order effects - participants may do better or worse when doing a similar task twice. May reduce the validity of results.
Participants may guess the aims and change their behaviour.
Matched Pairs
Two groups of participants are used but they are also related to each other by being paired on participant variables that matter for the experiment.
Outline the strengths of matched pairs
Participant variables - participants are matched on a variable that is relevant to the experiment. This enhances the validity of the results.
No order effects - participants are only tested once so no practice or fatigue effects can affect validity of results.
Outline the limitations of matched pairs
Matching isn’t perfect - time consuming, can’t control all relevant variables, may not fully address participant variables.
More participants - need twice as many participants as repeated measures for same data. More time is spent recruiting which is expensive.
Laboratory Experiment
A controlled environment where extraneous and confounding variables can be regulated. The researcher manipulates the IV and records the effect on the DV.
Outline the strengths of a lab experiment
EVs and CVs can be controlled - the effect of EVs and CVs on the DV can be minimised. Cause and effect between the IV and DV can be demonstrated (high internal validity).
Can be easily replicated - due to the standardised procedure, the experiment can be repeated. If the results are the same this confirms the validity.
Outline the limitations of a lab experiment
May lack generalisability - controlled lab environment may be artificial and participants may be aware they are being studied. Behaviour may not occur naturally and therefore has low external validity and cannot be generalised to everyday life.
Demand characteristics - may affect results
Field Experiment
An experiment that takes place in a natural setting. The researcher manipulates the IV and records the effect on the DV.
Outline the strengths of a field experiment
Natural environment - participants may be more comfortable in their own environment, results are more generalisable to everyday.
Participants are unaware they are being studied - more likely to behave normally, greater external validity.
Outline the limitations of a field experiment
More difficult to control CVs - observed changes in DV may not be due to the IVs. More difficult to establish cause and effect.
Ethical issues - participants may not have given informed consent. Invasion of privacy.
Natural Experiment
An experiment where the change in the IV is not brought about by the researcher but would have happened even if the researcher had not been there. Researcher records effect on DV.
Outline the strengths of a natural experiment
May be the only ethical option - it may be unethical to manipulate the IV, e.g. studying the effects of institutionalisation on children, so NE may be the only causal research that can be done for such topics.
Greater external validity - involve real-life issues so findings are more relevant.
Outline the limitations of a natural experiment
The natural event may only occur rarely - reduces opportunity for research and limit the scope for generalising findings to other situations.
Participants aren’t randomly allocated - experimenter has no control over which participants are placed in which condition as the IV is pre-existing. May result in CVs that aren’t controlled.
Quasi-experiment
IV is based on a pre-existing difference between people, e.g. age or gender. No one has manipulated this variable, it simply exists. DV may be naturally occurring (e.g. exam results) or may be measured by the experimenter.
Outline the strengths of a quasi experiment
Often high control - shares some strengths of lab experiments.
Comparisons can be made between people - the IV is a difference between people e.g. people with autism and people without. This means comparisons can be made.
Outline the limitations of a quasi experiment
Not randomly allocated - participant variables may have caused the change in the DV.
Causal relationships not demonstrated - researcher doesn’t manipulate/ control the IV. We cannot say for certain that any change in the DV was due to the IV.
Population
The large group of people that a researcher is interested in studying.
Sample
A group of people who take part in a research investigation. Drawn from a target population and it is presumed to be representative of that population.
Generalisation
The extent to which findings and conclusions from an investigation can be broadly applied to the population.
Bias
Over or under-represented sample. Limits the extent to which generalisations can be made to target population.
Opportunity Sample
People who are most available i.e. ones who are nearest/ easiest to obtain.
- Asking people nearby.
Evaluate opportunity sampling
✓ Quick method - convenient, one of the most popular sampling methods.
✗ Inevitably biased - sample is unrepresentative, drawn from a very specific area. Findings cannot always be generalised.
Volunteer Sample
Participants select themselves. Researchers advertise, for example, by placing an ad in the newspaper.
Evaluate volunteer sampling
✓ Participants are willing - know how much time and effort is involved and so are likely to engage more.
✗ Likely to be a biased sample - participants may share the same characteristics, e.g. keen and curious. Generalisation is limited.
Random Sample
Every person in the target population has an equal chance of being selected.
- Lottery method - all members are given a number and placed into a hat.
Evaluate random sampling
✓ Free from researcher bias - researcher has no influence over who is selected.
✗ Representation not guaranteed - still could produce a biased sample which limits ability to generalise.
Systematic Sample
Participants are selected using a set ‘pattern’ (sampling frame)
- Every nth person is selected from a list of the target population.
Evaluate systematic sampling
✓ Unbiased - first item is usually selected at random. Objective method.
✗ Time and effort.
Stratified Sample
Participants are selected according to their frequency in the target population.
- Subgroups (or strata) are identified, e.g. gender, age. Relative percentages of strata in population are reflected in the sample.
Evaluate stratified sampling
✓ Representative method - generalisability more likely.
✗ Stratification is not perfect - strata can’t reflect all the ways in which people are different. Complete representation isn’t possible.