Research Methods - KT

Experimental method

Involves the manipulation of an independent variable (IV) to measure the effect on the dependent variable (DV). Experiments may be laboratory, field, natural or quasi

Aim

A general statement of what the researcher intends to investigate, the purpose of the study

Hypothesis

A clear, precise, testable statement that states the relationship between the variables to be investigated. Stated at the outset of any study

Directional hypothesis

States the direction of the difference or relationship

Non-directional hypothesis

Does not state the direction of the difference or relationship

Variables

Any ‘thing’ that can vary or change within an investigation. Variables are generally used in experiments to determine if changes in one thing result in changes to another

Independent variable (IV)

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 (DV)

The variable that is measured by the researcher. Any effect on the DV should be caused by the change in the IV

Operationalisation

Clearly defining variables in terms of how they can be measured

Extraneous variable (EV)

Any variable, other than the independent variable (IV), that may affect the dependent variable (DV) if it is not controlled. EVs are essentially nuisance variables that do not vary systematically with the IV

Confounding variables

A kind of EV but the key feature is that a confounding variable varies systematically with the IV. Therefore we can’t tell if any change in the DV is due to the IV or the confounding variable

Demand characteristics

Any cue from the researcher or from the research situation that may be interpreted by participants as revealing the purpose of an investigation. This may lead to a participant changing their behaviour within the research situation

Investigator effects

Any effect of the investigator’s behaviour (conscious or unconscious) on the research outcome (the DV). This may include everything from the design of the study to the selection of, and interaction with, participants during the research process

Randomisation

The use of chance methods to control for the effects of bias when designing materials and deciding the order of experimental conditions

Standardisation

Using exactly the same formalised procedures and instructions for all participants in a research study

Experimental design

The different ways in which participants can be organised in relation to the experimental conditions

Independent groups design

Participants are allocated to different groups where each group represents one experimental condition

Repeated measures

All participants take part in all conditions of the experiment

Matched pairs design

Pairs of participants are first matched on some variable(s) that may affect the dependent variable. Then one member of the pair is assigned to Condition A and the other to Condition B

Random allocation

An attempt to control for participant variables in an independent groups design which ensures that each participant has the same chance of being in one condition as any other

Counterbalancing

An attempt to control for the effects of order in a repeated measures design: half the participants experience the conditions in one order, and the other half in the opposite order

Laboratory (lab) experiment

An experiment that takes place in a controlled environment within which the researcher manipulates the IV and records the effect on the DV, whilst maintaining strict control of extraneous variables

Field experiment

An experiment that takes place in a natural setting within which the researcher manipulates the IV and records the effect on the DV

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. The researcher records the effect on a DV they have decided on

Quasi-experiment

A study that is almost an experiment but lacks key ingredients. The IV has not been determined by anyone (the researcher or any other person) - the ‘variables’ simply exist, such as being old or young. Strictly speaking this is not an experiment

Population

A group of people who are the focus of the researcher’s interest, from which a smaller sample is drawn

Sample

A group of people who take part in a research investigation. The sample is drawn from a (target) population and is presumed to be representative of that population, i.e. it stands ‘fairly’ for the population being studied

Sampling techniques

The method used to select people from the population

Bias

In the context of sampling, when certain groups are over- or under-represented within the sample selected. For instance, there may be too many younger people or too many people of one ethnic origin in a sample. This limits to the extent to which generalisations can be made to the target population

Generalisation

The extent to which findings and conclusions from a particular investigation can be broadly applied to the population. This is possible if the sample of the participants is representative of the target population

Ethical issues

These arise when a conflict exists between the rights of participants in research studies and the goals of research to produce authentic, valid and worthwhile data

BPS code of ethics

A quasi-legal document produced by the British Psychological Society (BPS) that instructs psychologists in the UK about what behaviour is and is not acceptable when dealing with participants. The code is built around 4 major principles: respect, competence, responsibility and integrity

Pilot study

A small-scale version of an investigation that takes place before the real investigation is conducted. The aim id to check that procedures, materials, measuring scales etc. work. The aim is also to allow the researcher to make changes or modifications if necessary

Naturalistic observation

Watching and recording behaviour in the setting within which it would normally occur

Controlled observation

Watching and recording behaviour within a structured environment, i.e. one where some variables are managed

Covert observation

Participants’ behaviour is watched and recorded without their knowledge or consent

Overt observation

Participants’ behaviour is watched and recorded with their knowledge and consent

Participant observation

The researcher becomes a member of the group whose behaviour he/she is watching and recording

Non-participant observation

The researcher remains outside of the group whose behaviour he/she is watching and recording

Behavioural categories

When a target behaviour id broken up into components that are observable and measurable (operationalisation)

Event sampling

A target behaviour or event is first established, then the researcher records this event every time it occurs

Time sampling

A target individual or group is first established then the researcher records their behaviour in a fixed time frame, say, every 60 seconds

Self-report technique

Any method in which a person is asked to state or explain their own feelings, opinions, behaviours and/or experiences related to a given topic

Questionnaire

A set of written questions (sometimes referred to as ‘items’) used to assess a person’s thoughts and/or experiences

Interview

A ‘live’ encounter (face-to-face or on the phone) where one person (the interviewer) asks a set of questions to asses an interviewee’s thoughts and/or experiences. The questions may be pre-set (as in a structured interview) or may develop as the interview goes along (unstructured interview)

Open questions

Questions for which there is no fixed choice of response and respondents can answer in any way they wish. For example, ‘Why did you take up smoking?’

Closed questions

Questions for which there is a fixed choice for responses determined by the question setter. For example, ‘Do you smoke? (yes/no)’

Correlation

A mathematical technique in which a researcher investigates an association between two variables, called co-variables

Co-variables

The variables investigated within a correlation, for example height and weight. They are not referred to as the independent and dependent variables because a correlation investigates the association between the variables, rather than trying to show a cause-and-effect relationship

Positive correlation

As one co-variable increases so does the other. For example, the number of people in a room and noise tend to be positively correlated

Negative correlation

As one co-variable increases, the other decreases. For example, the number of people in a room and amount of personal space tend to be negatively correlated

Zero correlation

When there is no relationship between the co-variables. For example, the association between the number of people in a room in Manchester and the total daily rainfall in Peru is likely to be zero

Qualitative data

Data that is expressed in words and non-numerical (although qualitative data may be converted to numbers for the purposes of analysis)

Quantitative data

Data that can be counted, usually given as numbers

Primary data

Information that has been obtained first-hand by a researcher for the purposes of a research project. In psychology, such data is often gathered directly from participants as part of an experiment, self-report or observation

Secondary data

Information that has already been collected by someone else and so pre-dates the current research project. In psychology, such data might include the work of other psychologists or government statistics

Meta-analysis

The process of combining the findings from a number of studies on a particular topic. The aim is to produce an overall statistical conclusion (the effect size) based on a range of studies. A meta-analysis should not be confused with a review where a number of studies are compared and discussed

Descriptive statistics

The use of graphs, tables and summary statistics to identify trends and analyse the sets of data

Measures of central tendency

The general term for any measure of the average value in a set of data

Mean

The arithmetic average calculated by adding up all the values in a set of data and dividing by the number of values

Median

The central value in a set of data when values are arranged from lowest to highest

Mode

The most frequently occurring value in a set of data

Measures of dispersion

The general term for any measure of the spread or variation in a set of scores

Range

A simple calculation of dispersion in a set of scores which is worked out by subtracting the lowest score from the highest score and adding 1 as a mathematical correction

Standard deviation

A sophisticated measure of dispersion in a set of scores. It tells us by how much, on average, each score deviates from the mean

Scattergram

A type of graph that represents the strength and direction of the relationship between co-variables in a correlational analysis

Bar chart

A type of graph in which the frequency of each variable is represented by the height of the bars

Histogram

A type of graph which shows the frequency but, unlike a bar chart, the area of the bars (not just the height) represents frequency. The x-axis must start at a true zero and the scale is continuous

Normal distribution

A symmetrical spread of frequency data that forms a bell-shaped pattern. The mean, median and mode are all located at the highest peak

Skewed distribution

A spread of frequency data that is not symmetrical, where the data clusters to one end

Positive skew

A type of frequency distribution in which the long tail is on the positive (right) side of the peak and most of the distribution is concentrated on the left

Negative skew

A type of frequency distribution in which the long tail is on the negative (left) side of the peak and most of the distribution is concentrated on the right

Statistical testing

Provides a way of determining whether hypotheses should be accepted or rejected. By using statistical test we can find out whether differences or relationships between variables are significant (meaningful) or are likely to have occurred by chance

Sign test

A statistical test used to analyse the difference in scores between related items (e.g. the same participants tested twice). Data should be nominal or better

Peer review

The assessment of scientific work by others who are specialists in the same field, to ensure that any research intended for publication is of a high quality

Economy

The state of a country or region in terms of the production and consumption of goods and services