Key Science Skills

IV

The variable that is changed or “manipulated” by the experimenter to observe whether it affects another variable and what those effects are.

DV

The variable that is measured to assess the effects of the IV is called the dependent variable.

Hypothesis

PIDDI - Population, IV (2nd condition), Direction, DV, IV (2nd condition)

Random sampling

ensures that every member of the of the population has an equal chance of being selected as a participant

Stratified sampling

Population is divided into strata (subgroups) and then a sample from each strata/group is chosen in the same proportion as the population

Random Allocation

involves dividing the sample into groups in a way that means that each participant has an equal chance of being placed into the experimental or control group

Population

refers to the entire group of research interest from which a sample is drawn. 

Sample

is a subsection or smaller group, of research participants selected from a larger group (population) of research interest

SNAGS - subjects, number, age, gender, special characteristics

Voluntary Participation

individuals should be able to freely choose to take part in a study without being coerced, tricked or manipulated

Informed consent

• participants must be informed of the type of study & purpose and give full written consent

• for children and intellectually disabled people, the experimenter must obtain written agreement from the person responsible for the participant ( guardian/parent

Withdrawal rights

participants are free to decline to participate, or to withdraw from a study at any time

Confidentiality

• ensuring privacy, protection & security of a participant’s personal information and the anonymity of individual results

• details of their involvement in a study cannot be revealed unless their written consent is obtained

Deception

• to disguise the full intent of the study

• deception is only allowed when the participants knowing what the study’s purpose is may affect the results

Debriefing

• at the end of every study

• participants offered counselling, feedback & questions about the study

• deception would be revealed if necessary

• any harm done should be reversed

Controlled experiment

•An experimental investigation of the relationship between one or more IVs and a DV, controlling all other variables

•Specifically looking at whether there is a cause-effect relationship between an IV and a DV

Advantages + Limitations of controlled experiment

Advantages

• •The researcher can infer causal relationships between, and draw conclusions about, specific variables

• •Provide researchers with a high level of control of conditions and variables

• •Follow a controlled procedure, so can be repeated testing reliability

• •A hypothesis can be tested faster than in real world settings

• •Extraneous variables and confounding variables can potentially be minimised/ controlled for

Limitations

• •Participants response may be affected by the setting, generally not reflective of real life

• •Open to error or experimenter effect

• •Can be time consuming and expensive

• •Confounding and extraneous variables often still occur

Between subject design

• Different participants are randomly allocated to two separate control & experimental groups

Advantages of between subject design

• less time consuming than within subjects

• No order effects

• Low rate of participant withdrawal as they only complete one condition

Limitations of between subjects design

• requires more participants than within subjects

• Participant related variables likely to cause issues when comparing groups, reducing validity - performance, bias

Difference between control group and experimental group

experimental- exposed to the IV.

control - The participants are NOT exposed to the IV and provide a baseline measure

Correlational study

a non-experimental study in which researchers observe and measure the relationship between two or more variables without any active control or manipulation of them in order to:

• Understand the relationship or association existing between variables

• Identify which factors may be of greater importance

• Make predictions

Advantages + Limitations of Correlational Study

Advantages

• There is no manipulation of variable required

• The direction and strength of a relationship between variables can be determined

• ideas for future research can be provided

• Can be conducted in naturalists settings, findings are therefore applicable to real world settings

• Can be used to determine the repeatability, reproducibility and validity of measurements

Limitations

• No conclusions about cause and effect can be drawn

• Correlation does not equal or imply causation

• Can be influenced by extraneous variables

• A large amount of data is needed

Within-subjects design

an investigation design in which all participants in the sample are involved in both the experimental and control conditions

Advantages + Limitations of Within subjects

Advantages

• Reduces participant related variables compared to between subjects

• •Can be completed with fewer people than between subjects

Limitations

• •May result in order effects (practice or fatigue related)

• •Participants dropping out can impact the outcome

• •Time consuming

Mixed design

an investigation design that combines elements of a between subjects design and a within subjects design

advantages + limitations of mixed design

advantages

• •Results can be compared across groups and across individuals

• •Multiple experimental conditions can be compared to a baseline control group

• •Testing multiple IVs in one investigation can be time and cost effective

limitations

• •Can be costly and time consuming

• •Demanding for researchers and assistants to be across multiple methods (experimenter effect may increase)

• •Less control over differences in participant variables between groups in the between subjects element

Extraneous Variables

variables other than the independent variable, that may cause changes in the dependent variable

Confounding Variables

extraneous variables that were not controlled for and have influenced the DV

Order effect

in within-subjects design:

the order in which both the conditions of the IV are administered may cause order effects

• Learning from one condition to the next (practice effect)

• Boredom

• Fatigue

• Carry over effect: the influence of one condition on the performance of a subsequent condition

Situational variables

Environmental factors that may affect the dependent variable

• temp

• lighting

• time of day

Experimenter bias

the expectations that experimenters may have, whether about the participants or the results, possibly influencing how they conduct the research or interpret the results.

Placebo effect

a change in a participant’s behaviour due to their belief that they are receiving some experimental treatment and they respond by that belief, rather than to the effect of the IV

can be overcome by giving control group a placebo so nobody knows whether they have real thing

Individual Participant Differences

the qualities and characteristics of each of the people used in the experimental and control groups (age, ability, attitude, intelligence, mood, cultural background, experience etc) which could affect the results

Non-standardised instructions and procedures

errors can be introduced when procedures and instructions are not exactly the same (standardised) for participants in each condition.

Demand Characteristics

cues in an experiment that suggest the kind of response that the experimenter wants or expects and may influence or bias a participant’s response, thereby distorting the results

Case study

in-depth investigation of an individual, group, or particular phenomenon that contains a real or hypothetical situation and includes the complexities that would be encountered in the real world

• Medical histories

• interviews

• Observations

• Reports

Advantages + Limitations of Case Studies

advantage

• Useful method of obtaining detailed information

• Allow researchers to investigate impractical, rare situations

• provide a ‘snapshot’ of the real-life experience of one or more individuals at a particular time, in a particular situation

• provide rich qualitative data

• act as a basis for further research

limitation

• Cannot test or establish a cause-effect relationship

• Small sample size

• Results cannot be generalised to a wider population

• Subject to research bias and errors

• Cause and effect is difficult to determine

• Can be very time consuming

Fieldwork

any research involving observation and interaction with people and environments in real-world settings, conducted outside of the lab

Advantages + Limitations of Fieldwork

advantages

• •Can be conducted in naturalistic settings – increasing ecological validity

• •Can provide detailed data

• •May be used for a broad range of methodologies

• •May occur over an extended period

• •Rich qualitative data can be obtained

limitations

• •Can be time-consuming and expensive

• •Generally does not lead to conclusions about cause and effect

• •Due to lengthy procedures in a real-world setting, fieldwork is difficult to replicate in order to verify results (low reliability)

• •Difficult to control the environment and therefore extraneous variables

• •Observed behaviour is subjective and open to interpretation and bias by the researcher

Fieldwork - self reports

Self report is a participant’s answers to questions presented by the researcher.

Advantage

•Useful method to collect data on how people think, feel and behave

•Efficient way to collect data from a large number of people in a relatively short amount of time

•Easy to replicate

•Can be anonymous which allows people to be more honest about ‘sensitive’ topics

limitations

•Assumes that people are self-aware of their personal experiences and behaviour

•Social desirability effect – participants may intentionally give false or misleading answers to create a favourable impression of themselves

Fieldwork - observational study

Observational studies involves collection of data by carefully watching and recording behaviour as it occurs without any intervention or manipulation of the behaviour being observed.

advantage

•In naturalistic observations, researchers can watch and record spontaneous, everyday behaviour without the need for manipulation or intervention

•In naturalistic observations, enables researchers to gain more accurate information about the typical behaviours of people

•Structured observations (particularly with checklists) enhances the accuracy of data collection and therefore the results obtained

limitation

•Often lacks a representative sample

•Observer bias could occur (where the researcher sometimes unconsciously distorts what they observe so that it ‘fits’ what they hope to see

Product, Process or System Development

the design or evaluation of an artefact/ product, process or system to meet a human need.

Advantages + Limitations of Product, Process or System Development

Advantages

• Creates products, processes and systems that meet a human need

Limitations

• •Can be expensive and time-intense

Literature review

the processes of collating and analysing secondary data related to the scientific findings and/or viewpoints of others to answer a question or provide background information

Advantages + Limitations of Literature Review

Advantages

• Provides background information on specific phenomena that can be used to inform new studies

• •Provides information about current understandings

• •May highlight patterns of knowledge or gaps of knowledge

Disadvantage

• •Can be time-consuming

• •May be difficult if research on a particular topic is lacking

• •Difficult to ensure all research is consulted

• •Selection bias may result

Modelling

the construction and/ or manipulation of either a physical model or conceptual model that represents a system involving concepts that help people understand or simulate the system

Advantages + Limitations of Modelling

Advantages

• May provide explanatory tools

• •Physical modelling supports the research to know, understand and problem solve

• •Aids to simplify and explain certain phenomena

Limitations

• •May over simplify or inaccurately represent ideas

Simulation

a process of using a model to study the behaviour of a real or theoretical system.

Advantages + Limitations of Simulation

Advantages

• •Provides insight into potential circumstance or events

• •Allows difficult things to see to be viewed (e.g. neurons)

• •Allows dangerous or time consuming events/ processes to be seen

Disadvantages

• •Can be time-consuming and expensive

• •Subject to programming and human error

  •May not always be accurate or truly reflect reality

Respect

Recognition that each human being has value

Integrity

The commitment to searching for knowledge and understanding, and the honest reporting of all sources of information and results, whether favourable or unfavourable, in ways that permit scrutiny and contribute to public knowledge and understanding

Justice

Research that has concern for the use of fair procedures and fair distribution of costs and benefits

Beneficence

there must be a reason to conduct research and a commitment to maximising the benefits and minimising risks and harms

Non-maleficence

the principle of avoiding causing harm - any position of course of action should not be disproportionate to the benefits from any position or course of action

Classification & Identification

arranging objects, events or phenomena into distinct, manageable categories.

to be classified as identifying with a particular group infers such phenomena share similar qualities or characteristics and will behave in predictably common ways.

Advantages + Limitations of Classification and Identification

Advantages

• Provides a common language to communicate

• •Aids to simplify, explain and describe complex phenomena

• •Theories about labelled phenomena can be formed

Limitations

• •May over-simplify reality

• •Labels and language can be inaccurate and create bias, stereotyping, prejudice or discrimination

• •Classifications may be based on subjective criteria

Conclusion

a statement about the findings of study

• should address the aim and state if the hypothesis was supported

• statement on generalizability

• recommendations for future research

• considers if any change in the independent variable is due to the dependent variable

Internal validity

whether a study measures what it sets out to investigate

External validity

whether results can reliably be generalised to the wider population or not

Repeatability

the closeness of agreement between successive measurements carried out under the same conditions

Reproducibility

the agreement of results measured under changed conditions

Double blind

neither the participants nor the experimenter know which condition the participants were allocated to.

Single blind

where the participants are unaware of the experimental condition that they’re in

Accuracy

how close a measurement is to the true value of the quantity being measured

Precision

how close a set of measurement values are to each other

Random error

an error that creates unpredictable variations in the measurement process and results in a spread of readings

Systematic error

an error that causes readings to differ from the true value by a consistent amount each time a measurement is made

Personal error

a mistake, miscalculation or observer error made when conducting research

Opinion

a judgement that is not necessarily based on proof

Anecdote

a short personal account of an event

Evidence

a verified fact

random sampling

selecting participants from the population in a way that means each member of the population has an equal chance of being selected to participate in the study