Paper 3

Random Sampling

Definition:
Every individual in the target population has an equal chance of being selected.

Characteristics:

1. Reduces selection bias, increasing generalizability.

2. Often requires a full list of the population (sampling frame).

3. Can be time-consuming and impractical for large or hard-to-reach populations.

Convenience Sampling

Definition:
Participants are selected based on their easy availability and willingness to take part.

Characteristics:

1. Quick, inexpensive, and easy to conduct.

2. High risk of sampling bias — not representative.

3. Relies on readily available subjects.

4. Results may not generalize to the larger population.

Volunteer Sampling

Definition:
Participants self-select by responding to an advertisement or request to take part.

Characteristics:

1. Participants are often more motivated or interested in the topic.

2. Risk of volunteer bias (e.g., more confident or opinionated people).

3. Ethical as participants willingly consent.

Purposive Sampling

Definition:
Participants are selected based on specific characteristics relevant to the research.

Characteristics:

1. Useful for qualitative research or studying specific traits.

2. Not intended to be generalizable to the whole population.

3. Researcher judgment is used to select "information-rich" cases.

Snowball Sampling

Definition:
Existing participants refer or recruit additional participants from their network.

Characteristics:

1. Effective for accessing hidden or hard-to-reach populations (e.g., drug users).

2. Can lead to sampling bias due to social networks.

3. Sample may become homogeneous due to connections between participants.

Observation

Qualitative
Definition:
A method where researchers watch and record behavior as it occurs naturally or in a controlled setting.

Characteristics:

1. Can be naturalistic (in real-world settings) or controlled (in lab settings).

2. May be overt (participants know they’re being observed) or covert (they don’t know).

3. Data can be structured (using checklists) or unstructured (more descriptive and open-ended).

Benefit:
Provides direct insight into actual behavior, not just self-reported attitudes.

Case Study

Qualitative
Definition:
An in-depth investigation of a single individual, group, or event.

Characteristics:

1. Uses multiple data sources (interviews, observations, documents).

2. Often longitudinal (over time).

3. Focuses on rare or unique cases.

Benefit:
Provides rich, detailed insights that may not emerge in other methods.

Focus Groups

Qualitative
Definition:
A moderated group discussion used to explore participants’ views and experiences.

Characteristics:

1. Typically 6–10 participants.

2. Open-ended questions guided by a facilitator.

3. Interaction between participants can reveal shared beliefs or disagreements.

Benefit:
Generates diverse perspectives and ideas in a short time.

Un-Structured Interviews

Qualitative
Definition:
Open-ended, flexible interviews where questions are not pre-planned.

Characteristics:

1. Conversation-like, guided by participant responses.

2. Rich qualitative data.

3. Harder to replicate and analyze.

Benefit:
Allows deep exploration of the participant’s perspective.

Semi - Structured Interviews

Qualitative
Definition:
Interviews with a mix of pre-set questions and follow-up probes.

Characteristics:

1. Combines structure with flexibility.

2. Easier to compare than unstructured interviews.

3. Still allows for exploration of unexpected topics.

Benefit:
Balances depth and consistency across interviews.

Structured Interviews

Qualitative
Definition:
Interviews with pre-determined, fixed questions asked in a set order.

Characteristics:

1. Highly standardized and easy to replicate.

2. Quantifiable responses.

3. Limits in-depth exploration.

Benefit:
Useful for comparing responses and analyzing data systematically.

Lab Experiments

Quantitative
Definition:
Experiments conducted in a controlled environment with manipulated variables.

Characteristics:

1. High internal validity due to control over extraneous variables.

2. Often uses random assignment.

3. May lack ecological validity.

Benefit:
Enables strong cause-and-effect conclusions.

Field Experiments

Quantitative
Definition:
Experiments conducted in natural settings with manipulated variables.

Characteristics:

1. High ecological validity.

2. Lower control over variables than in a lab.

3. Participants may not know they're in a study.

Benefit:
More realistic behavior from participants.

Natural Experiments

Quantitative
Definition:
Experiments where the independent variable occurs naturally (not manipulated by the researcher).

Characteristics:

1. High ecological validity.

2. No random assignment.

3. Often used in situations where manipulation would be unethical.

Benefit:
Allows study of real-world effects (e.g., policy changes, natural disasters).

Questionnaires

Quantitative
Definition:
A set of written questions to collect self-report data from participants.

Characteristics:

1. Can be closed or open-ended.

2. Easy to distribute to large samples.

3. Risk of social desirability or misunderstanding.

Benefit:
Efficient way to gather large amounts of data quickly.

Quasi-Experiments

Quantitative
Definition:
Studies that test cause-and-effect but lack random assignment to conditions.

Characteristics:

1. Participants are assigned to groups based on existing traits.

2. Some control, but not fully experimental.

3. Often used when randomization is impractical or unethical.

Benefit:
Useful for studying variables that can’t be ethically manipulated (e.g., age, gender).

Correlation

Quantitative
Definition:
A statistical method that examines the relationship between two variables.

Characteristics:

1. Shows direction and strength of a relationship.

2. Does not imply causation.

3. Often visualized with scatterplots and calculated with correlation coefficients (e.g., Pearson’s r).

Benefit:
Useful for identifying patterns or relationships that warrant further study.