CFS Quality Control & Process Improvement 2 — Questions and Answers
Question 1: During a floodplain survey QC review, a field technician discovers that benchmark elevations were not re-verified after equipment was moved to a new setup station. What is the most appropriate corrective action?
- Accept the data if loop closure error is within tolerance
- Re-run all field observations from the original benchmark (Correct answer)
- Discard all data collected after the move and resurvey
- Average the elevations from adjacent benchmarks
Correct answer: Re-run all field observations from the original benchmark
When benchmark elevations are not re-verified after an instrument move, re-running observations from the original benchmark ensures the vertical control chain remains unbroken.
Question 2: Which statistical tool is most appropriate for identifying whether a floodplain elevation measurement process is in statistical control over time?
- Pareto chart
- Control chart (X-bar and R chart) (Correct answer)
- Fishbone diagram
- Scatter plot
Correct answer: Control chart (X-bar and R chart)
Control charts (X-bar and R charts) monitor process mean and variation over time to determine if a measurement process is in statistical control.
Question 3: A QC audit of FEMA FIRM panel revisions finds that 15% of BFE calculations contain rounding errors. According to continuous process improvement principles, what should be the FIRST step?
- Retrain all staff on BFE calculation procedures
- Identify the root cause of the rounding errors (Correct answer)
- Implement an automated rounding check in the software
- Issue a corrective action memo to field crews
Correct answer: Identify the root cause of the rounding errors
Root cause analysis must precede corrective action to ensure the intervention addresses the actual source of defects rather than symptoms.
Question 4: When performing a QC check on a LiDAR-derived DEM used for floodplain mapping, what is the primary accuracy metric specified by FEMA for ground point verification?
- Horizontal RMSE ≤ 1.0 meter
- Vertical RMSE ≤ 9.25 cm (0.3 ft) for flat terrain
- Positional accuracy of ≤ 0.5 meter CE90
- Absolute vertical accuracy ≤ 0.15 meter at 95% confidence (Correct answer)
Correct answer: Absolute vertical accuracy ≤ 0.15 meter at 95% confidence
FEMA's Guidelines and Specifications for Flood Hazard Mapping Partners require LiDAR ground data to meet absolute vertical accuracy of ≤ 0.15 m at the 95% confidence level.
Question 5: A process improvement team notices that LOMR submittals from a particular firm are rejected by FEMA at a rate three times higher than the industry average. Which quality tool best helps visualize the most frequent rejection reasons?
- Pareto chart (Correct answer)
- Control chart
- Scatter diagram
- Flowchart
Correct answer: Pareto chart
A Pareto chart ranks defect categories by frequency, allowing teams to focus improvement efforts on the vital few causes responsible for most rejections.
Question 6: In the context of CFS quality management, what does a 'level of service' document for floodplain survey deliverables primarily establish?
- The hourly billing rates for survey personnel
- The minimum accuracy, completeness, and format standards for deliverables (Correct answer)
- The schedule for FEMA FIRM panel updates
- The chain of custody for field equipment calibration records
Correct answer: The minimum accuracy, completeness, and format standards for deliverables
A level of service document defines the minimum standards for accuracy, completeness, and format that survey deliverables must meet to be accepted.
Question 7: A surveying firm implements a peer review process requiring an independent licensed surveyor to check all BFE cross-sections before submittal. This practice is best described as which type of quality control activity?
- Preventive quality control (Correct answer)
- Corrective quality control
- Detective quality control
- Predictive quality control
Correct answer: Preventive quality control
Independent peer review before submittal is a preventive quality control activity because it intercepts errors before they enter the official record.
CFS Quality Control & Process Improvement 2
During a floodplain survey QC review, a field technician discovers that benchmark elevations were not re-verified after equipment was moved to a new setup station.
What is the most appropriate corrective action?