In CSI / CDT usage, quality assurance (QA) and quality control (QC) are distinct concepts:
Quality Assurance (QA) focuses on planning, processes, and preventive actions put in place before and during the work to help ensure the required quality will be achieved. It is about systems and procedures.
Quality Control (QC) focuses on inspection, testing, and verification to determine whether the constructed work conforms to the requirements of the Contract Documents.
Typical examples:
QA examples (process-oriented):
Developing and following a project-specific quality plan.
Coordinating scheduling and sequencing of the work so trades do not interfere with one another and work is done under appropriate conditions.
Prequalification of contractors, subcontractors, and testing agencies.
Establishing and enforcing submittal procedures and preinstallation meetings.
QC examples (inspection/testing):
Field testing (e.g., concrete cylinder tests, soil compaction tests).
Visual inspection of installed work.
Checking that installed products match submittals and specifications.
Looking at the options:
A. Performing compaction testing – This is a field test used to verify densities and is clearly quality control, not QA.
B. Field observations – These are performed by the A/E or others to observe and verify that work appears to be in general conformance; this is quality control.
C. Validating quantities for payment – This is a contract administration / cost control activity, not primarily a quality activity.
D. Scheduling and sequencing of the work – This is planning and coordination done in advance so the project can proceed efficiently, correctly, and without damaging completed work. Because it is a procedure-based, preventive activity, CSI places this type of planning under quality assurance.
Therefore, the example of quality assurance is “Scheduling and sequencing of the work” (Option D).
Relevant CSI / CDT References (titles only, no links):
CSI Project Delivery Practice Guide – sections on “Quality in Project Delivery” and distinctions between QA and QC.
CSI Construction Specifications Practice Guide – discussions of quality requirements, testing, and inspection.
CDT Body of Knowledge – domain on “Construction Phase: Quality Assurance and Quality Control.”
