Northwest Fisheries Science Center

Fisheries Observation Science Topics


Jon McVeigh
Program Manager
Staff Directory

Data Quality Control

The WCGOP uses the following procedure to ensure that the quality of data collected is maintained:

  1. Observers are trained by knowledgeable staff including biologists and former observers. A combination of lectures, hands-on activities, in-class exercises, and homework assignments prepare observers for the challenges of sampling at-sea.
  2. Data are collected at-sea by the observer following protocols in the WCGOP Manual.
  3. Observers keep logbooks detailing the events of each trip. The logbook includes basic deck schematics, communication logs, Vessel Safety and Equipment Test checklists, and Observer Safety Surveys. There is also a Daily Notes section outlining the day-to-day activities aboard each vessel. Any tows/sets during which sampling problems occurred are documented in the logbook.
  4. Observers provide detailed accounts of the sampling methods used at-sea by completing the Sampling Verification form. Debriefers use these forms to identify errors in sampling methodology and to provide guidance on more effective sampling strategies.
  5. Accuracy of species identification is verified through the use of Species Identification forms. Observers must complete a set number of these forms per trip. These forms are then used by debriefers to identify and correct any errors in the identification of species encountered.
  6. Automated error checks are conducted during initial data entry into the secure Oracle database system.
  7. Observers periodically undergo debriefing during deployment. Debriefing consists of an interview with WCGOP staff to discuss sampling methods and resolve data errors. The debriefing process includes:
    • Calculation, Data Form, and Sampling Methodology Checks - The debriefer checks all calculations for accuracy, reviews data forms for completeness, and ensures appropriate sampling methodologies were employed.
    • Evaluation - Observers are evaluated on their performance based upon WCGOP generated criteria. Areas for improvement are identified and tracked for progress.
    • Data Entry Check - Electronic data are compared to the raw data for keypunch errors. Also, all corrections discovered during debriefing are updated in the database program.
  8. Database Quality Control Queries - Quality control queries are run to detect data that fall outside specified ranges and identify other inconsistencies between data elements. These database quality control queries are run regularly on all data collected during a specified time period.
  9. Database Update - Any data flagged by automated quality control queries are reviewed by the debriefer. Any necessary changes in the raw (paper) data are updated in the electronic database.