Time study – determining allowances Which technique is most appropriate for determining realistic allowances (e.g., fatigue, delay) to apply to observed normal time?

Introduction / Context:
Standard time = normal time * allowance factor. While performance rating converts observed time to normal time, realistic allowances must capture the proportion of time lost to fatigue, personal needs, and unavoidable delays.

Given Data / Assumptions:

• Observations are taken over representative periods.
• Multiple categories of time use exist (productive, setup, idle, delays).
• Objective is to estimate allowance percentages credibly.

Concept / Approach:
Work sampling (random instantaneous observations) estimates the fraction of time spent in various categories using statistical inference. The estimated proportion of non-productive but unavoidable time becomes the allowance.

Step-by-Step Solution:
Define categories (e.g., working, setup, planned delay, personal, unavoidable idle).Plan random observations over days/shifts.Record the state seen at each observation.Estimate proportion p for each category; compute allowance = sum of relevant p's.Apply allowance factor to normal time to obtain standard time.

Verification / Alternative check:
Confidence intervals from binomial approximation validate precision; repeating samples on different weeks tests stability.

Why Other Options Are Wrong:
Performance rating adjusts effort, not allowances. Acceptance sampling and linear regression address quality and modeling, not allowance estimation. Earned value is a project control technique.

Common Pitfalls:
Non-random observations, too few samples, or misclassification of categories bias the allowance estimates.

Final Answer:
Work sampling