Take 10: Issue 28 Data Quality

01 Oct 2021 The Navigator

Assessing data quality is key to safe navigation. Here are ten points to help you ask the right questions

1 Garbage in / garbage out 

Navigators need to make critical decisions based on the best data and information they can get. Poor data or information can lead to bad decisions. Validate whenever you can! 

2 Validate

There are various ways to validate data and information – not least by using common sense and good seamanship. Don’t forget to validate what you see by eye by electronic means if possible – nothing is infallible. 

3 Data and information are different

Data tends to be facts, whereas information is usually assumptions or estimates based on those facts. For example, the temperature and wind direction can be measured but forecasts have to be predicted. If it is interpreted wrongly, even accurate data can lead to inaccurate information. 

4 Golden rule

Never trust a position gained by only one means. Good navigators are always looking for ways to validate their position. This does not change in the age of GNSS. 10 take Assessing data quality is key to safe navigation. Here are ten points to help you ask the right questions 

5 Under Keel Clearance

Again, multiple forms of data all need to be accurate; depth gained from hydrographic survey, vessel draft, state of tide, position, prevalence of shifting sand/mud, vessel’s roll and pitch, etc… Always validate when you can. 

6 Manage risks

When data or information can’t be validated, try to manage your risks. Give yourself greater searoom, change routes, reduce speed, ask advice or even abort a manoeuvre until risks can be reduced. 

7 Know your source

Knowing the source of information can be useful. Information gained by hearsay or non-official internet sites should raise a healthy level of questioning. 

8 Latency

Is the time lag between when something is measured or confirmed and when it is used. Accurate data and information sometimes changes over time and a good navigator will always check the dates and times to judge if it can still be trusted. 

9 Share

As always, share your knowledge about information quality, discuss with your fellow professionals how verification can best be made, mentor others and allow them to mentor you. 

10 Feedback

If you find a fault in data or information, it is important to report it if appropriate. Few people provide bad information on purpose and most will be very thankful for feedback – and then they will try to validate as well.