The (un)reliability of purchased data
From Cyburbian Cardinal: I have often purchased data from vendors (ESRI, Claritas, etc.) who package their market potential and sales estimates. All too often, I find I have to modify it if not throw it away altogether and prepare my own estimates. Their estimates are based on formulas that may work adequately in middle- or upper-income white trade areas, but do not work where there is a significant minority population, in central city neighborhoods, or most rural locations.
The latest case is a study I am working on in the south. According to the data provided, people in this trade area spend less than 20 percent of what a normal household would spend on furniture. They do not buy any shoes.
Is this some kind of comment on the south? Po' southern folk don't wear no shoes? They just sit on a tree stump whittlin' all day?
The problem I see is that many of the people who use this data do not have the education and experience needed to look at it critically. They accept it as fact. It gets included in plans and decisions are made based on it. I see as many consultants guilty of this as planners in communities.
Maybe I am just venting. Or maybe I am a bit curious to see what experiences other people have had. Was the data good? Bad? How likely are you to notice when something is going on when the data indicates otherwise?
I think this is the reason that more information is not shared through GIS. I am just as much to blame as the next person. I understand what the issues are with my data and I can make adjustments to it or with it but the second I share it someone will critique what I do and it won't hold up to that scrutiny.
That is one of the reasons that our local utility companies will not share is because of the quality of the information they have. I certainly don't understand why they don't GPS pipelines and such, especially as easy as it is to do now.
The forgotten part of GIS - the metadata. Good metadata should tell you about the quality, how the info was derived, etc.
Our economic development folks used to purchase data from a vendor. Our department finally got hold of it and systematically discredited every bit of it. We are now the source for most of their information, and the little bit they purchase gets vetted by our department.
The data are put together to help companies sell things to people with money. It is not put together with an eye towards scientific or government accuracy concerns. It is very problematic, as you point out.
That's just the problem. I was going to use this data for a market analysis.
Cardinal, have you tried Buxton?
I used them for a project in Texas and it replaced older Claritas data. Their sales rep really took care of me- get your corporate credit card ready...
Oh God, no!!! :-o
Stay away! Stay away!
agreed
I agree but am also confounded as to what to call it. When I say land use planning, people are still confused, when I say urban design, people really have no clue. The associations that come with the term placemaking make my skin crawl. So I don't know. Wasn't this a useful post? :)
The Social Compact - Drilldown Market Analysis
I recommend taking a look at The Social Compact for their "drilldown market analysis" approach to accounting the spending power (rather than earning power) of under-represented populations. I believe the Brookings Institute is affiliated with this program. Definitely an interesting approach to economic development research.
i don't have the source in front of me, but i have read in a few places about the under-representation that exists in market data for minority or impoverished neighborhoods. i'll try to find it. this underrepresentation, as you have pointed out, can lead to faulty decision-making, since the data being analyzed is incomplete.