LESSON 36 - NON-PROBABILITY SAMPLING DESIGNS: CONVENIENCE, PURPOSIVE, QUOTA & SNOW-BALL DESIGNS

Item: LESSON 36 - NON-PROBABILITY SAMPLING DESIGNS: CONVENIENCE, PURPOSIVE, QUOTA & SNOW-BALL DESIGNS
Rating: 3
Author: PostSingularity Institute

by Prof. Lydiah Wambugu

Humanities, Social Sciences & Thought Science — General & History GPResearch and information: general GPSResearch methods

🎙 Prof. Lydiah Wambugu 👥 29K 📅 June 7, 2021 ⏱ 15 min 👁 6K 📄 tutorial 🧭 2026-08-17

Available in: English (current) Français

Keywords

samplingqualitative researchconveniencepurposivequotasnowball

Summary

This lesson, part of a research methods course, introduces non-probability sampling designs, also known as qualitative or non-random sampling. The instructor explains that in these designs, the probability of selecting any individual from the population is unknown, and they are typically used in qualitative research where generalization is not the primary goal. Four main designs are discussed: convenience sampling, which involves selecting participants based on easy accessibility; purposive (or judgmental) sampling, where the researcher selects participants based on specific characteristics or knowledge; quota sampling, which involves segmenting the population into subgroups and then selecting a predetermined number from each; and snowball sampling, where existing participants recruit future participants from their networks. The lesson highlights the strengths and limitations of each design, emphasizing their utility in exploratory research and when studying hard-to-reach populations. The instructor also notes that these designs are often used when probability sampling is impractical or impossible. The video concludes by summarizing the key points and encouraging viewers to access the full course for more details.

168 words

Critical Evaluation

Value of the Information & Strength of the Argument

The video provides a solid introduction to non-probability sampling designs, clearly explaining each type and its applications. The instructor uses examples to illustrate the concepts, which enhances understanding. However, the argumentation is not deeply critical; it presents the designs as standard tools without delving into controversies or debates within the field. The value lies in its pedagogical clarity, making it useful for beginners in research methodology.

Scientific Rigor, Source Quality, Title Accuracy

The video does not cite specific academic sources, but it is part of a structured course, and the instructor appears to have expertise in the field. The title accurately matches the content. The description provides links to the course and social media, but no direct references to academic literature. The transcription is garbled, which may affect the accuracy of the information presented, but the core concepts are correctly outlined.

150 words

Title / Content Match

The title accurately reflects the content, which covers the four main non-probability sampling designs in detail.

Quality & Reliability

6/10

The video provides a clear and structured overview of non-probability sampling designs, but the transcription is heavily garbled, making it difficult to verify the accuracy of the content. The instructor appears knowledgeable, but the lack of clear citations and the poor audio quality reduce reliability.

Key Moments

Markers derived by PSI from the transcript: the creator did not define chapters.

Cited Sources

Research Methods Course — Full course access mentioned in the video description.
YouTube Channel — Subscription link provided in the description.
LinkedIn — Social media link from the description.
Facebook — Social media link from the description.
Instagram — Social media link from the description.
WhatsApp — Contact link from the description.

Concurring Sources

Convenience sampling — Provides a standard definition and examples.
Purposive sampling — Explains the method and its subtypes.
Quota sampling — Describes the technique and its advantages.
Snowball sampling — Details the process and its applications.

Contribution & Novelties

The video offers a clear and structured overview of non-probability sampling designs, which is particularly useful for students new to qualitative research. It distinguishes each design and provides practical examples. However, it does not introduce novel concepts or advanced discussions.

Pour aller plus loin :

Convenience sampling — Provides a detailed definition and examples.
Purposive sampling — Explains the rationale and types.
Quota sampling — Discusses the method and its applications.
Snowball sampling — Overview of the technique and its use in research.

83 words

Radar Profile

The radar profile shows moderate scores across all dimensions, with a slight peak in quantity of information. This indicates a balanced but not exceptional educational video, suitable for introductory learning but lacking depth and critical analysis.

Reliability 5/10

💬 No comments were provided for analysis.