Control cycle; quality control factors

Project control cycle

The project control cycle is the repeated process of planning, measuring, comparing, analysing and correcting that keeps the project on its time, cost and quality targets. The arrow from box 5 back to box 1 is the feedback: the plan is updated and the cycle starts again.

+--------------+     +------------------+
| 1 Plan:      |     | 2 Implement and  |
| baseline of  |---->| measure actual   |
| time, cost,  |     | progress         |
| quality      |     +--------+---------+
+------^-------+              |
       |                      v
+------+-------+     +------------------+
| 5 Take       |     | 3 Compare actual |
| corrective   |     | with plan and    |
| action /     |     | find variance    |
| re-plan      |     +--------+---------+
+------^-------+              |
       |                      v
       |             +------------------+
       +-------------| 4 Analyse causes |
                     | and decide       |
                     +------------------+

1. Set the baseline plan: approved scope, schedule, budget and quality standards.
2. Measure progress: record the actual work done, cost spent and quality results through site reports, measurement books and inspections.
3. Compare actual with planned values and find the variance (schedule, cost, quality).
4. Analyse the variance: find the causes (late material, low productivity, design change, weather) and forecast the effect on the completion date and final cost.
5. Take corrective action: add resources, work overtime, re-sequence activities, change the method, or revise the plan with approval.
6. Report and update: inform management, update the plan, and repeat the cycle at the next review period (feedback).

Factors to be considered in quality control

1. Specifications and standards: clear drawings, specifications and codes (Nepal Building Code, IS, NS) with acceptance limits.
2. Quality of materials: testing of cement, steel, aggregate, bricks and bitumen before use; approved sources.
3. Workmanship and skill: trained labour and supervisors; method statements.
4. Equipment and tools: suitable, calibrated and well-maintained machines and testing instruments.
5. Inspection and testing: a plan of tests (cube test, density test, slump test), their frequency and sampling.
6. Supervision and organisation: clear responsibility; a qualified quality engineer.
7. Documentation: records of tests, approvals and non-conformance reports.
8. Environment and site conditions: weather, curing, storage of materials.
9. Time and cost pressure: rushing or low rates reduce quality, so quality must be planned into the budget and schedule.
10. Corrective and preventive action: a rework or rejection procedure, and feedback to avoid repeated defects.