ISO 24153:2009

Overview

ISO 24153:2009 – Random Sampling and Randomization Procedures establishes internationally recognized methods for random sampling and randomization. Published by the International Organization for Standardization (ISO), this standard ensures that procedures for selecting random samples are unbiased and transparent, serving a crucial role in quality control, designed experiments, auditing, and survey sampling. The standard outlines mechanical, tabular, and computer-based approaches for generating randomness, ensuring the traceability and reproducibility of results when randomization is contractually or legally required.

Key Topics

• Random Sampling Methods:

  • Mechanical devices: Utilization of urns, coins, and dice for random selection without or with replacement.
  • Random number tables: Using tables of random numbers to assign and select samples.
  • Computer algorithms: Portable and auditable software-based random number generation for both general and quality management uses.

• Randomization Fundamentals:

  • Ensuring each unit or combination has an equal probability of selection, minimizing bias.
  • Procedures for both simple random sampling and specialized forms such as stratified, cluster, and multi-stage sampling.

• Auditability and Compliance:

  • Guidelines for maintaining records of randomization processes for validation by auditors or regulatory bodies.
  • Emphasis on reproducibility of selection, especially using computer-generated algorithms with settable seeds for traceability.

• Scope and Applicability:

  • Applicable wherever regulations, contracts, or other standards mandate random selection or assignment.
  • Methods support contexts including acceptance sampling, survey sampling, audit sampling, and designed experimental assignment.

• Limitations:

  • The standard does not dictate which sampling strategy or sample size to use for any specific application but focuses on how to implement randomization reliably.

Applications

ISO 24153:2009 is broadly relevant in sectors where unbiased selection or assignment is essential to ensure process quality and statistical validity. Its recommended approaches are used for:

• Acceptance Sampling: Randomly selecting units from a batch for inspection in quality management, reducing sampling bias and supporting compliance with global standards.
• Survey Sampling: Ensuring scientifically valid population estimates by unbiased selection of survey subjects or items.
• Audits and Compliance: Supporting objectivity in selecting samples for audit of quality management systems, facilitating regulatory or third-party review.
• Experiment Design: Randomizing the allocation of treatments and defining evaluation order in scientific, medical, agricultural, and industrial experiments to defend against selection bias.
• Regulatory Compliance: Providing documented, verifiable methods for organizations required to demonstrate the use of random processes in quality assurance or regulatory contexts.

Related Standards

To address situations outside ISO 24153:2009’s procedural focus-such as strategy selection or determining sample sizes-consult these supporting international standards:

• ISO 2859 (all parts): Sampling procedures for inspection by attributes.
• ISO 3951 (all parts): Sampling procedures for inspection by variables.
• ISO 8422: Sequential sampling plans for inspection by attributes.
• ISO 8423: Sequential sampling plans for inspection by variables.
• ISO 13448: Acceptance sampling based on allocation of priorities.
• ISO 14560: Attribute sampling for specified quality levels.
• ISO 18414: Accept-zero sampling systems for outgoing quality control.
• ISO 21247: Combined accept-zero sampling and process control.
• ISO 11648: Statistical aspects of sampling from bulk materials.

ISO 24153:2009 complements these standards by detailing universal, unbiased methods for random selection, vital to compliance, data integrity, and statistical defensibility in regulated, industrial, scientific, and auditing contexts.