Research Methods: Planning and Conducting Research

What you'll learn

This guide covers everything you need to know about planning and conducting psychological research for Edexcel GCSE Psychology. You'll learn how to design valid studies, select appropriate samples, apply ethical guidelines, and collect reliable data. These skills are essential for Paper 2 and will help you evaluate studies across all topic areas.

Key terms and definitions

Aim — A general statement of what the researcher intends to investigate, outlining the purpose of the study.

Hypothesis — A clear, precise, testable statement that predicts the relationship between variables or the difference between conditions.

Independent variable (IV) — The variable that the researcher manipulates or changes in an experiment to observe its effect on the dependent variable.

Dependent variable (DV) — The variable that is measured in an experiment to see if it has been affected by changes to the independent variable.

Operationalisation — The process of defining variables in measurable, observable terms so they can be tested objectively.

Sampling technique — The method used to select participants from the target population for a research study.

Informed consent — An ethical requirement where participants agree to take part in research after being given full information about what their participation involves.

Pilot study — A small-scale trial run of a research study conducted before the main investigation to identify and resolve potential problems.

Core concepts

Developing research aims and hypotheses

Every psychological investigation begins with an aim that identifies the general area of interest. For example: "To investigate whether music affects concentration in teenagers."

From the aim, researchers develop a hypothesis — a specific, testable prediction. There are two types:

Null hypothesis — Predicts there will be no difference or relationship between variables (e.g., "There will be no difference in concentration scores between teenagers who listen to music and those who do not").

Alternative hypothesis — Predicts there will be a difference or relationship (e.g., "Teenagers who listen to music while studying will have lower concentration scores than those who study in silence").

Alternative hypotheses can be:

• Directional (one-tailed) — States the direction of the predicted difference (e.g., scores will be "higher" or "lower")
• Non-directional (two-tailed) — Predicts a difference but not its direction (e.g., "there will be a difference")

Researchers use directional hypotheses when previous research suggests a specific outcome. Non-directional hypotheses are used when there is insufficient prior evidence.

Variables and operationalisation

To test a hypothesis, researchers must clearly define their variables through operationalisation. This means specifying exactly how variables will be measured or manipulated.

Vague: "Music affects concentration" Operationalised: "Participants who listen to music at 70 decibels will recall fewer words from a 20-word list than participants in silence"

Extraneous variables are factors other than the IV that might affect the DV. Researchers must identify and control these. For example:

• Time of day (participants tested at different times may have different energy levels)
• Instructions given (inconsistent instructions could affect performance)
• Environmental factors (temperature, noise, lighting)

Confounding variables are extraneous variables that systematically vary with the IV, making it impossible to determine what caused changes in the DV. These invalidate the research.

Sampling techniques

Researchers cannot usually study entire populations, so they select a sample — a subset of the target population. The sampling method affects how representative and generalisable the findings are.

Random sampling — Every member of the target population has an equal chance of being selected (e.g., names drawn from a hat, computer-generated selection).

Strengths:

• Unbiased selection
• Representative if sample is large enough

Limitations:

• Time-consuming to obtain complete population list
• Selected participants may refuse to take part

Opportunity sampling — Recruiting people who are readily available and willing to participate (e.g., approaching students in a school cafeteria).

Strengths:

• Quick and convenient
• Cost-effective

Limitations:

• Biased (sample may not represent target population)
• Researcher bias in selecting participants

Stratified sampling — Dividing the population into subgroups (strata) based on relevant characteristics, then selecting participants proportionally from each stratum.

Strengths:

• Representative of key population characteristics
• Allows comparison between subgroups

Limitations:

• Requires detailed population information
• Time-consuming to organise

Systematic sampling — Selecting every nth person from a population list (e.g., every 5th person on a school register).

Strengths:

• Unbiased if list order is random
• Simpler than random sampling

Limitations:

• Not truly random
• Biased if list has a pattern

Ethical considerations

The British Psychological Society (BPS) provides ethical guidelines that all researchers must follow to protect participant welfare.

Informed consent — Participants must understand what the study involves, what will be expected of them, and their right to withdraw. For children under 16, parental consent is required.

Right to withdraw — Participants can leave the study at any time without giving a reason and can withdraw their data after participation.

Deception — Misleading participants or withholding information should be avoided unless absolutely necessary for valid results. When deception is used, researchers must debrief participants afterwards.

Debriefing — At the study's conclusion, researchers must inform participants of the true aims, answer questions, and address any concerns.

Protection from harm — Participants should not experience physical or psychological harm beyond what they would encounter in everyday life. This includes stress, embarrassment, or loss of self-esteem.

Confidentiality — Participant data should be kept anonymous and secure. Personal information should not be disclosed without permission.

Privacy — Participants have the right to control information about themselves. Researchers should not observe people in situations where they expect privacy without consent.

Types of data and measurement

Researchers collect two main types of data:

Quantitative data — Numerical information that can be statistically analysed (e.g., test scores, reaction times, number of words recalled).

Strengths:

• Objective and easy to analyse
• Allows comparison between groups
• Can identify patterns and trends

Limitations:

• May lack detail about reasons for behaviour
• Doesn't capture complexity of human experience

Qualitative data — Non-numerical information expressed in words (e.g., interview transcripts, diary entries, open-ended questionnaire responses).

Strengths:

• Rich, detailed information
• Captures participants' perspectives
• Can reveal unexpected findings

Limitations:

• Subjective interpretation by researcher
• Difficult to compare between participants
• Time-consuming to analyse

Pilot studies and research design

A pilot study is a small-scale preliminary investigation conducted before the main study. Typically involving 5-10 participants, it tests whether:

• Instructions are clear
• Equipment functions properly
• The task takes an appropriate amount of time
• Participants understand what is required
• The research design produces measurable results

Benefits of pilot studies:

• Identifies problems with procedures or materials
• Allows modifications before investing time and resources
• Checks that data collection methods work effectively
• Saves money by preventing flawed main studies

Based on pilot study findings, researchers make adjustments to improve the main investigation.

Reliability and validity in research design

Reliability refers to consistency — whether the study produces the same results when repeated under similar conditions. Researchers can check reliability by:

• Test-retest method (conducting the same study with same participants at different times)
• Inter-observer reliability (checking multiple researchers record observations consistently)

Validity refers to whether the study measures what it claims to measure and whether results are genuine. Types include:

Internal validity — Whether the observed effects are genuinely due to the manipulation of the IV rather than confounding variables.

External validity — Whether findings generalise beyond the specific research setting:

• Ecological validity (generalising to real-life settings)
• Population validity (generalising to other groups)
• Temporal validity (generalising to other time periods)

Researchers improve validity by:

• Controlling extraneous variables
• Using standardised procedures
• Selecting representative samples
• Creating realistic research settings

Worked examples

Example 1: Writing operationalised hypotheses (3 marks)

Question: A psychologist wants to investigate whether caffeine improves memory in students. Write a suitable operationalised alternative hypothesis for this study.

Mark scheme answer: Students who consume 100mg of caffeine (one mark for operationalising IV) will recall more words from a 30-word list (one mark for operationalising DV) than students who consume no caffeine (one mark for comparison/control condition).

Examiner note: The hypothesis must specify exactly how both variables will be measured. Simply stating "caffeine improves memory" would score 0 marks as neither variable is operationalised.

Example 2: Identifying and explaining sampling methods (4 marks)

Question: A researcher approaches students leaving the library at lunchtime and asks if they will complete a questionnaire about study habits. Identify the sampling method used and explain one limitation of this method. (4 marks)

Mark scheme answer: This is opportunity sampling (1 mark) because the researcher selects participants who are conveniently available at that time and location (1 mark).

One limitation is that the sample may not be representative of all students (1 mark) because students who use the library at lunchtime may be more studious than those who do not, creating bias in the findings about study habits (1 mark).

Examiner note: The explanation must link the limitation specifically to the context provided. Generic statements about sampling methods score fewer marks than contextualised answers.

Example 3: Ethical issues (6 marks)

Question: A researcher wants to observe how teenagers behave when they think they are alone in a waiting room. Discuss two ethical issues with this study. (6 marks)

Mark scheme answer:

Issue 1: Lack of informed consent (1 mark). Participants are unaware they are being observed, so they cannot agree to participate in the study (1 mark). This violates their right to make an informed decision about involvement (1 mark).

Issue 2: Invasion of privacy (1 mark). Participants expect privacy in a waiting room and are not aware their behaviour is being recorded (1 mark). This could cause embarrassment or distress when they discover they were observed without permission (1 mark).

Examiner note: 'Discuss' requires both identification and elaboration. Each ethical issue should be named, explained, and related to the specific research scenario for full marks.

Common mistakes and how to avoid them

• Writing vague hypotheses — Always operationalise both IV and DV with specific, measurable terms. "Music affects concentration" is an aim, not a hypothesis. "Participants listening to music at 70 decibels will recall fewer words than those in silence" is properly operationalised.

• Confusing aims and hypotheses — Aims are general statements about what you're investigating. Hypotheses are precise, testable predictions about what you expect to find. Don't use the same sentence for both.

• Mixing up sampling techniques — Learn the defining features of each method. Random sampling uses equal chance for everyone; opportunity sampling uses whoever is available; stratified divides population into groups first.

• Generic evaluation points — When discussing ethical issues or limitations, always apply your knowledge to the specific study in the question. "This could cause harm" is too vague — explain what specific harm might occur in that particular context.

• Forgetting to justify research decisions — When asked why a researcher chose a particular method or hypothesis type, explain with reference to the research context. "They used a directional hypothesis because previous research by Smith (2018) showed music reduced concentration" is better than "because they knew the direction."

• Misunderstanding pilot studies — Pilot studies test procedures, not hypotheses. They identify practical problems, not whether the hypothesis is correct. Don't confuse them with the main investigation.

Exam technique for "Research Methods: Planning and Conducting Research"

• Command words matter — "Identify" requires naming only (1 mark). "Explain" needs reasoning (usually 2-3 marks). "Discuss" requires detailed analysis of strengths and/or weaknesses (typically 3-6 marks). Match your answer length to the marks available.

• Contextualise your answers — When questions provide a research scenario, relate every point back to that specific context. Examiners reward application of knowledge, not just recall. Use details from the question in your answer.

• Structure extended answers — For 4-6 mark questions, use clear paragraphs. Make your point, explain it, then link it to the research context. One well-developed point scores more than three superficial statements.

• Show examiner knowledge — Use correct terminology (operationalisation, confounding variable, stratified sampling) to demonstrate understanding. This signals to examiners that you've mastered the material and often triggers higher mark bands.

Quick revision summary

Research planning begins with an aim and operationalised hypothesis predicting the relationship between clearly defined variables. Researchers select participants using sampling techniques (random, opportunity, stratified, or systematic) and must follow BPS ethical guidelines including informed consent, right to withdraw, debriefing, and protection from harm. Pilot studies test procedures before the main investigation. Valid research controls extraneous variables and uses appropriate measures to collect reliable quantitative or qualitative data. Strong research design ensures both internal validity (measuring what's intended) and external validity (generalisable findings).