Classification of Sampling Plan in Garments Industry
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| Classification of Sampling Plans in the Garments Industry – An overview of how samples are selected, inspected, and approved to ensure quality at every stage of production. |
Sampling in garments is done to ensure product quality, consistency, and buyer satisfaction. Sampling plans can be classified in several ways:
Based on Purpose of Sampling
a) Development Samples
Used to develop the style before order confirmation.
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Proto Sample
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Fit Sample
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Size Set Sample
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Counter Sample
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Photo/Styling Sample
b) Pre-Production (PP) Samples
Used before bulk production to finalize all details.
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PP Sample
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Sealing Sample
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Wash/Color Test Sample
c) Production Samples
Created during and after bulk production.
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Inline Sample
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Top of Production (TOP) Sample
Based on Sampling Technique
a) Random Sampling
Every piece has an equal chance of selection.
Used for inline inspection & final inspection.
b) Systematic Sampling
Samples selected using fixed intervals (e.g., every 10th garment).
Used for large production lines.
c) Stratified Sampling
Sampling by dividing into groups (size, color, PO).
Ensures all variations are checked.
d) Judgment/Subjective Sampling
Inspector selects suspicious or critical pieces.
Used for risk-based assessment.
Based on AQL & Inspection Level
(Specified by ISO 2859 / ANSI Z1.4)
Inspection Levels
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General Level I – Low inspection
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General Level II – Standard (most common)
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General Level III – Tight inspection
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Special Level S1–S4 – Small sample or critical test
AQL Levels (Acceptance Quality Limit)
Common AQLs:
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2.5 → Major defects
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4.0 → Minor defects
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1.5 or 1.0 → High-risk / sensitive products
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0.65 / 0.25 → Premium or safety items
Based on Stage of Manufacturing
a) Fabric Sampling
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Lab-dip
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Handloom
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Swatch
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Shrinkage/Wash Test Sample
b) Trims & Accessories Sampling
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Button, zipper, label, care tag sample
c) Garment Sampling
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Pre-wash / post-wash samples
Based on Buyer Requirement
a) Marketing / Salesman Samples
For buyer presentation or photography.
b) Pre-line / Line Review Samples
To approve styling direction.
c) Shipping Samples
Sent to the buyer along with the shipment for reference.
Based on Quantity of Sample
Sampling plans are classified into three major types based on how many samples are taken during inspection:
Single Sampling Plan
Definition:
Only one fixed sample size is drawn from the lot for inspection.
How it Works:
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You check one sample set.
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Based on Ac (Acceptance number) and Re (Rejection number), you accept or reject the lot.
Example:
If sample size = 80, AQL = 2.5 →
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Accept if ≤ 5 defects
Where Used:
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Final inspection
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Inline QC
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Most common in garment industry
Double Sampling Plan
Definition:
Sampling is done in two steps, depending on the results of the first sample.
How it Works:
Step 1:
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Inspect first sample
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If defects are clearly within Ac or over Re → accept or reject
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If results fall in the gray zone, take a second sample
Step 2:
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Inspect second sample
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Combine results
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Make final decision
Benefit:
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Reduces inspection time when products are clearly good or clearly defective.
Where Used:
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Used when the buyer requires higher accuracy
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Cost-conscious inspections
Multiple Sampling Plan
Definition:
Sampling is done in multiple (more than two) rounds until a clear decision is reached.
How it Works:
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Very similar to double sampling
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But may involve 3–7 sampling stages
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Stop whenever results meet the accept/reject criteria
Benefit:
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Most efficient in terms of average sample size
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Very precise decision-making
Drawbacks:
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Complicated to manage
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Rarely used in garment factories
Where Used:
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High-risk orders
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Expensive products
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Large-scale QC organizations
Summary Table
| Sampling Plan | Number of Samples | Usage | Complexity |
|---|---|---|---|
| Single | 1 | Most common | Simple |
| Double | 2 | Moderate-risk inspection | Medium |
| Multiple | 3+ | High accuracy needed | High |
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