What is Acceptance Sampling?

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What is Acceptance Sampling? Blog Image


The VVPAT-based audit of Electronic Voting Machines (EVMs) is a typical case of “lot acceptance sampling”, a statistical quality control technique widely used in industry and trade.

About Acceptance Sampling:

  • It is a statistical measure used in quality control.
  • It allows a company to determine the quality of a batch of products by selecting a specified number for testing.
  • It tests a representative sample of the product for defects. 
  • The quality of this designated sample will be viewed as the quality level for the entire group of products.
  • The process involves first, determining the size of a product lot to be tested, then the number of products to be sampled, and finally the number of defects acceptable within the sample batch.
  • Products are chosen at random for sampling.
  • It does not assure the quality of the complete set of products from which the sample is derived.
  • Origin:
    • Acceptance sampling in its modern industrial form dates from the early 1940s.
    • It was popularized by Dodge and Romig and originally applied by the U.S. military to the testing of bullets during World War II. 
  • Need for Acceptance Sampling:
    • A company cannot test every one of its products at all times.
    • There may be too many to inspect at a reasonable cost or within a reasonable timeframe.
    • Also, comprehensive testing might damage the product or make it unfit for sale in some way. 
    • Testing a small sample would be indicative without ruining the bulk of the product run.

Q1: What is Voter Verifiable Paper Audit Trail (VVPAT)?

It is an independent system that consists of two parts, namely, a VVPAT Printer and VVPAT Status Display Unit (VSDU) attached to the Electronic Voting Machines (EVMs), that allow the voters to verify that their votes are cast as intended. When a vote is cast, a slip is printed containing the serial number, name, and symbol of the candidate and remains exposed through a transparent window for 7 seconds. Thereafter, this printed slip automatically gets cut and falls into the sealed drop box of the VVPAT. The results of EVMs can be verified using the slipskept in the drop boxes of VVPAT machines.

Source: The EVM-VVPAT case judgment is disappointing