key scientific skills Flashcards
operationalising IV & DV
involves defining how they will be manipulated or measured in the experiment (or other investigation).
- e.g: to measure intelligence — a score on a standardised intelligence test
random sampling
every member of the population has an equal chance of being selected for the sample
advantages:
* free from bias
* Quick and easy
disadvantages:
* may not be representative of the population
stratified sampling
population is broken into subgroups then selects participants from each group in the same proportion they appear in the population.
* e.g: 60% boys 40% girls in a school - choosing 6 boys 4 girls for an experiment
advantages:
* more representative of the population
disadvantages :
* time consuming
* resource intrensive
* results in a non-representative sample
convenience sampling
a sample is selected in the quickest and easiest way possible
advantages:
* time and cost effective and participants can be accessed relatively easily due to their availability
disadvantages
- not representative of the population.
controlled experiment
an experimental investigation to test the relationship between an IV and a DV, whilst controlling all other variables.
- eg: to test whether talking on a hand-held mobile phone while driving (one variable) causes or influences a change in driver reaction time (another variable)
controlled variable
considered to have an effect on the dependent variable in an experiment so it needs to be held constant (‘controlled’) to remove its potential effects.
- provides a baseline for comparison for the IV
correlational studies
used to investigate the relationship that exists between variables without any control over the setting in which the relationship occurs or any manipulation by the researcher
- there are no IVs or DVs, or control groups
- advantage: can be conducted outside an artificial laboratory situation where the results may also be more realistic.
- disadvantage: do not permit the researcher to draw firm conclusions about cause-and-effect relationships
self-report
a participant’s answers to questions presented by the researcher - relies on research participants’ accounts of their own experiences and behaviours.
- advantage: an efficient means of collecting data from a large number of people in a relatively short period of time
- disadvantage: social desirability effect (participants may intentionally give false or misleading answers to create a favourable impression of themselves.)
free-response and fixed-response questions
- allow participants to answer entirely as they want to
- present a number of ‘fixed’ alternative answers from which participants are required to choose
interview
involves questions that are asked by the researcher with the intention of prompting and obtaining specific information from an individual participant
questionnaire
a written set of questions or other prompts designed to draw out self-report information from participants on a topic of research interest
focus group
a small set of people who share characteristics and are selected to discuss a topic of which they have personal experience.
- a leader conducts the discussion and keeps it on target while also encouraging free-flowing, open-ended debate
observational study
involves collection of data by carefully watching and recording behaviour as it occurs without any intervention or manipulation of the behaviour being observed
- advantage: researchers can watch and record spontaneous, everyday behaviour without the need for any manipulation or intervention.
- disadvantage: cannot be used to determine the cause of the behaviour of interest that is observed, because many factors may influence that behaviour and there is a lack of control of such variables.
case study
an intensive, in-depth investigation of some behaviour, activity, event or problem of interest in a single individual, group, organisation or situation
- advantage: useful for tracking and describing experiences and change over time.
- disadvantage: cannot test or establish a cause–effect relationship
simulation studies
involve reproducing situations of research interest in a realistic way to investigate the behaviour and/or mental processes of individuals in that environment
- advantage: can also be used when an investigation is not ethically permissible
- disadvantage: environments are artificial and therefore the studies may lack realism
random errors
errors due to some chance factor or chance variation in a measurement
systematic errors
produced by some factor that consistently favours one condition rather than another
- affects accuracy
personal errors
a fault or mistake by the researcher
extraneous variables
variables which are not controlled for and has an unwanted effect on the results.
confounding variables
a variable other than the IV which has a systematic effect on the DV
- not controlled by the researcher
accuracy
relates to how close it is to the true value of the quantity being measured. Accuracy is not quantifiable; measurement values may be described as being more accurate or less accurate.
precision
refers to how closely a set of measurement values agree with each other
repeatability
- the closeness of the agreement between the results of successive measurements of the same quantity being measured, carried out under the same conditions of measurement
- same researcher
reproducibility
the closeness of the agreement between the results of measurements of the same quantity being measured, carried out under changed conditions of measurement.
- different researcher
validity
- a measurement is said to be valid if it measures what it is supposed to be measuring
- an experiment is said to be valid if it investigates what it sets out and/or claims to investigate.
types of validity
- internal validity refers to how successfully an experiment measures what it was intended to measure
- external validity refers to the extent to which research findings can be generalised to a greater population
individual/participant differences.
- difference in participants which bias results.
- control with matched participants.
placebo effect
experimental group administered treatment display physiological changes due to placebo and not due to treatment.
- control by giving control placebo (to raise baseline) or with single-blind in which participant does not know their group.
order effects
- occurs in within-subjects; participant’s performance is impacted by participation in previous trials.
- control with counterbalancing (groups do conditions in different, balanced, orders).
experimenter effects
- groups received varied treatment from experiments and bias results.
- control with standardized procedure between experimenters and/or double-blind in which neither experimenter nor participants know their group.
demand characteristics
- individuals think they know the expected results of the study and consciously change behaviour accordingly.
- hawthorne effect: subjects change behaviour when knowing they’re being watched; typically in observational studies.
- control with single or double blind.
unstandardised instructions/methods.
control with scripts, standardized procedures etc.
between-subjects
comparing participants in two or more different conditions - independent groups
- advantage: cost and time efficient
- disadvantage: individual participant differences across groups
within-subjects
an experimental design in which participants complete every experimental condition
- advantage: no participant differences, tracks individual change
- disadvantage: order effects—requires counterbalancing
mixed design
has both between-subjects factors and within-subjects factors.
- advantage: uses fewer participants
- disadvantages: more complex design to execute
primary data
info collected directly from the source by the researcher (or through others) for their own specific purpose.
secondary data
information that was not collected directly by the current researcher but was collected at an earlier time by someone else.
quantative data
information that is expressed numerically.
qualitative data
information that is not expressed numerically - descriptive
objective data
information that is observable, measurable, verifiable and free from the personal bias of the researcher.
subjective data
information that is based on personal opinion, interpretation, point of view or judgment.
confidentiality
the privacy, protection and security of a participant’s personal information in terms of personal details and the anonymity of individual results, including the removal of identifying elements.
debriefing
ensures that, at the end of the experiment, the participant leaves understanding the experimental aim, results and conclusions. Any participant questions are addressed, and support is also provided to ensure there is no lasting harm from their involvement in the study. Debriefing is essential for all studies that involve deception.
informed consent procedures
ensure participants understand the nature and purpose of the experiment, including potential risks (both physical and psychological), before agreeing to participate in the study. Voluntary written consent should be obtained by the experimenter and if participants are unable to give this consent, then a parent or legal guardian should provide this.
use of deception in research
is only permissible when participants knowing the true purpose of the experiment may affect their behaviour while participating in the study, and the subsequent validity of the experiment. The use of deception is discouraged in psychological research and used only when necessary.
voluntary participation
ensures that there is no coercion of or pressure put on the participant to partake in an experiment, and they freely choose to be involved.
withdrawal rights
involves a participant being able to discontinue their involvement in an experiment at any time during or after the conclusion of an experiment, without penalty.
- may include the removal of the participant’s results from the study after the study has been completed.
literature review
involves the collation and analysis of secondary data related to other people’s scientific findings and/or viewpoints in order to answer a question or provide background information to help explain observed events, or as preparation for an investigation to generate primary data
classification and identification
classification: the arrangement of a phenomenon, objects or events into manageable sets
identification: a process of recognition of phenomena as belonging to particular sets or possibly being part of a new or unique set.
modelling
involves construction and/or manipulation of either a physical model, such as a small- or large-scale representation of an object, or a conceptual model that represents a system involving concepts that help people know, understand or stimulate the system.
product, process or system development
design or evaluation of an artefact, process or system to meet a human need, which may involve technological applications in addition to scientific knowledge and procedures.
