Marine Debris Database

Understanding Reports

Generating meaningful data is something this database strives to do. However, the quality of the report is entirely dependent on the quality of the data that goes into it, as well as the the data's ability to mixed with other data. Before using data from the reports on this site, please be aware of the following so that you don't accidentally misrepresent the data.

Data Sheets

For every recorded event in this database, someone had to answer a specific set of questions about that event. However Beach Cleanup Event A (for example) will not answer the same questions about the event as Derelict Gear Removal Event B, because there are questions relevant and important to a beach cleanup that aren't to a derelict gear removal. For example:

  • Miles of beach cleaned
  • Estimated water depth

As you can see, the first question could not have a meaningful value collected for a derelict gear removal, and the same goes for the second question for a beach cleanup.

Going further, Beach Cleanup Event A may not answer the same questions as Beach Cleanup Event C if they were organized under different projects. Beach Cleanup Event A may collect a value for "number of plastic straws or stirrers collected", while Beach Cleanup Event C may only have a value "pounds of plastic collected".

In these cases, it can be said that each event used a different "data sheet" or in other words, used a different set of questions to record itself. As we can see, part of the reason for having different data sheets is due to collecting data about different types of events. The other reason we see different data sheets is because different, unrelated projects have sprung up over the years as people have gotten serious about cleaning their shores. There was no standard defined data sheet to use, and to this day have not committed to one because they have different processes or concerns.


What's the problem? Each cleanup team has collected their data, and their data has been imported into this database as it is. When you view event details, you see every value in the units they were collected in. However, if you want to view totals for these values across multiple events, we begin to see the issue:

If one team records 'Lbs of trash' and another team records 'Pounds of trash', everything is fine. This database is sophisticated enough to know that these two questions from different data sheets is the same question and can be aggregated. If one team records 'tons of trash', this database can still handle the necessary conversions to report a proper 'pounds of trash' value. However, if one event doesn't fill in a value for 'pounds of trash', or any weight of trash, even if they did clean trash off of the beach, that value cannot be derived and so a resulting sum across this and other events (also known as aggregation) will not accurately represent how many pounds of trash were really collected.


Because of this, the report feature will place a red 'i' next to any report value where one or more events being reported did not collect a value for that field. Hovering your mouse over the 'i' icon will tell you how many events had the value, and how many events are in the report so you can get a feel for how close the number might be to the actual truth, but under no circumstances can one of those values be considered accurate.