Earlier this year, I discussed the CRAAP test on spatial data quality, focusing on measures of Currency, Relevance, Authority, Accuracy, and Purpose. Since then, data quality has been a topic of discussion more frequently than ever before–not just in GIS circles, but in general daily news. Why is data quality important, and how can it be measured? I thought it therefore appropriate to create a new video reflecting upon some of these considerations.
We can download a wide variety of data; we can also stream data from a variety of sources that Jill Clark and I describe in the Spatial Reserves blog and in our book The GIS Guide to Public Domain Data. As data become easier to use, they become easier to misuse. It is easy to pull data from a variety of different sources, scales, dates, organizations, and lineages without a second thought, and then use those disparate data sources to make a key decision.
Don’t get me wrong–I don’t pine for the days when simply getting any data set into a GIS environment was a long, laborious process. I still vividly recall, for example, the month-long effort I went through in spring 1993 to get one county’s worth of census tract demographic data, plus streets and the census tract polygons, into ArcInfo version 4. I love the ability we have today to quickly gather and analyze data–and more and more of it possible in a cloud-based environment. I just want people to be more mindful than ever about the implications to making decisions with GIS. All of those decisions are ultimately based on the data that were used as inputs. And the above test is one way to assess whether that data is any good. And issues of data quality are fruitful topics to discuss in any GIS class to foster critical thinking.