23-Ind-A2 Analysis and Design of Work · December 2013
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
National Exams — December 2013 — 98-Ind-A2 Analysis and Design of Work. Three-hour, closed-book exam (approved Casio/Sharp calculator only); any five of the seven questions constitute a complete paper and only the first five answered in the answer book are marked — all seven are solved below for completeness. The source prints Question 3's second and third sub-parts both labelled “(iii)” (a typesetting slip); they are answered here in the marking-scheme order (i)/(ii)/(iii), 8/6/6 marks.
Reference texts: Niebel & Freivalds, Niebel’s Methods, Standards, and Work Design (13th ed.) — operations analysis, workplace/tool design and motion economy, stopwatch time study, performance rating and allowances, predetermined time systems (MTM/MOST), work sampling, wage-incentive and job-evaluation systems.
Question text not reproduced: the examination questions are © Engineers and Geoscientists BC. Open the official past paper (linked at the top of this page) to read the question, then follow the worked solution below.
Given.
| Work element | Observed time (min./pc.) | Rating % |
|---|---|---|
| 1. Load drill press | 0.20 | 115 |
| 2. Drill hole with automatic power feed | 0.25 | 100 |
| 3. Check tolerance (go/no-go gauge) | 0.10 | 110 |
| 4. Unload drill press | 0.15 | 120 |
Allowances: 5% personal + 5% unavoidable delays + 5% fatigue.
Find. The normal time and standard time for the operation, in min./pc.
Approach. Normalize each element’s observed time by its own performance rating, sum the elements to get the cycle normal time, then apply the total allowance (Niebel convention: allowances expressed as a percentage of normal time, added to it).
| Quantity | Value |
|---|---|
| Normal time, $NT$ | 0.770 min/pc |
| Total allowance, $A$ | 15% |
| Standard time, $ST$ | 0.8855 min/pc |
Under a wage-incentive program (Question 7(iii)) an operator’s pay is tied directly to output measured against the standard, so any drift between the standard and the true work content translates immediately into either an unearned pay windfall or an unfair, unachievable target. A standard left in place after a method, tool, material or equipment change becomes “loose” the moment the change makes the job easier than the standard assumed — operators then earn large, effortless bonuses, other operators demand the same loose rate on comparable jobs, and management loses the cost control the incentive was installed to provide. A standard that is tightened without a matching method improvement, conversely, provokes grievances, mistrust of the entire measurement system, and a slowdown in cooperation with future studies. Both failure modes are more damaging under incentive pay than under straight daywork, because money, not just planned output, is riding on the number.
A sound standards-maintenance program should: (1) require an automatic re-time trigger whenever a method, tool, fixture, material or equipment specification changes on a standardized job, rather than relying on someone to remember to request one; (2) run periodic audit studies (or work-sampling audits) on a sample of existing standards even where no known change occurred, to catch informal, undocumented method drift; (3) maintain a version-controlled record of every standard, the method it describes, and the date/reason for each revision, so a challenged standard can be defended or corrected from documented fact rather than memory; (4) involve employee or union representatives in the audit and revision process to maintain trust in the system; and (5) route every revision through the same rating/allowance discipline used to set the original standard (Question 3(ii)), so a maintained standard is not quietly re-derived by a different, less rigorous method than the one that set it.
Time per unit falls rapidly over the first units of a new job as the operator learns the motion pattern, then flattens toward a plateau as the method becomes habitual and further repetition yields only marginal gains — the classical learning curve, commonly modelled as $T(x)=T_1x^{-b}$ where $T_1$ is the first-unit time, $x$ is the cumulative unit count and $b$ is the learning-curve exponent.
The desirable stage to set the standard is on the plateau, once the curve has visibly flattened and successive units are no longer showing meaningful time improvement — not during the early, steep portion of the curve. A standard timed too early (during rapid learning) captures an inflated, not-yet-representative time that becomes loose within days as the operator continues to improve past it; a standard timed on the plateau reflects the pace a fully trained, experienced operator can sustain indefinitely, which is exactly what a standard is supposed to describe. In practice this means delaying the formal time study until cumulative output (or elapsed practice time) has reached the point where consecutive-unit times stop declining by more than a small, roughly constant percentage — verified by plotting a short run of recent cycle times and confirming the trend has levelled, not by picking an arbitrary unit count in advance.
