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Is your data STILL “CRAAP”?

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.

Is your data "CRAAP"?  Video.

Is your data “CRAAP”? Video.

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 this 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.

  1. Duane Marble
    October 28, 2013 at 5:57 pm

    I am in complete agreement with you on your statements regarding data quality. In the early years, I argued strongly for the provision of “data about data” and the concept of metadata was, it appeared, finally accepted. Current data users often have never heard of metadata and, if they have, they do not clearly understand it when they see it. However standard metadata does not solve the user’s problem of “knowing things about the data” – for example, you are utilizing data from several states where the data involves several data categories that are labeled the same but how do you know that the categories were defined in the same way in each of the states? Not paying attention to this kind of problem can easily result in good, old fashioned GIGO (garbage in – garbage out).

  2. November 1, 2013 at 2:29 am

    I also agree with you. The risks of inapropriate usages of data increases as people get their hands on spatial data taking for granted they fit their needs. Numerous papers and conferences have discussed this issue. Please visit our web site for examples of misuses and references to better protect the public (professional liability, privacy, copyright/copyleft, methods to reduce the risks of misuses, etc.). Most members involved in our GEOIDE project have published several papers and slides about these issues, you may find them on my personal web site (when I am co-authoring) or on their web site. See

    • josephkerski
      November 1, 2013 at 1:30 pm

      Professor Bedard: Merci for your comment and also the link to these very useful websites. I have not visited your university campus before but hope to someday. Your work on GEOIDE is extremely important to the entire community.

      –Joseph Kerski

  1. October 27, 2013 at 10:51 pm

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