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David Coffaro great bargain wines March 5, 2009

Posted by cnchapman in Blogroll, Wine.
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I haven’t written about wine yet on this blog, but it’s a big hobby of mine — both enjoying and also growing my own grapes for winemaking. One of my favorite wineries is a small, little-known winery in Sonoma County: David Coffaro winery. They make fabulous wines for people who love tasty, fruit-forward, big red wines. On top of that, Coffaro is a critic of high-priced wines. He prices his to make a “fair” return, no more. While many Dry Creek Valley Zinfandels are $40 or more, for instance, his are $28, or under $20 if purchased on futures.

In his New California Wine, Matt Kramer of Wine Spectator wrote that Coffaro “never makes a bad wine … I have friends who routinely order six or eight cases … they’re all lovely: intense, free of intrusive oakiness, and purely made.”

If you’re visiting Sonoma, they do a great tasting including both released wines and often a barrel tasting. If not, check out the online ordering and give them a chance. I recommend to pick 4 different blends or Zins, a great investment of about $100. My personal favorites are the Zinfandels, Block 4 field blend, and Escuro, a dark, rich, blend. David Coffaro Winery home page. Cheers! (And no, I have no connection to them, am just a fan, and tired of too much overpriced wine!)

Assessing persona prevalence empirically February 21, 2009

Posted by cnchapman in Blogroll, Market research, Technology, User research.
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I just obtained permission to post our latest paper on Personas. We argued previously that the personas method should not be considered to be scientific, and that a complete persona almost certainly describes few people or no one at all. In the new paper, we present a complete formal model, and evaluate the prevalence of “persona-like descriptions” with both analytical methods and empirical data. Full paper on persona prevalence.

There are two key implications here: (1) if you want to claim that a persona describes real people, you need strong multivariate evidence. (2) Without such evidence, we provide a formula you can use that will give a better estimate than simply assuming something. We show how this formula has a better than chance agreement with 60000 randomly generated persona-like descriptions in real data with up to 10000 respondents.

None of this says that personas are not inspiring or useful. It just says that they cannot be assumed to have verifiable information content, unless that is demonstrated empirically. As for alternatives to answer key design and business questions using empirical data, check out our paper on quantitative methods for product definition.

Personas February 8, 2009

Posted by cnchapman in Blogroll, Market research, Technology, User research.
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One of my papers from 2 years ago is still causing discussion: “The Personas’ New Clothes: Methodological and Practical Arguments against a Popular Method” by me and Russ Milham. Email from researchers I didn’t know led me to look up citations, and the article appears to be commonly cited when people present criticism of the personas method. Google search. The paper itself is here.

There are a few misunderstandings of our position out there. Our basic argument is simple. Persona authors often make two claims: (1) personas present real information about users; and (2) using personas leads to better products. In a nutshell, we argue that neither claim has been supported by empirical evidence; rather, the claims for personas’ utility are based on anecdotes, generally from their own authors or other interested parties (such as consultants selling them).

This does not mean that personas are bad, but they cannot be taken at face value. As researchers, we suggest that persona authors should either provide better evidence (and we suggest how) or make weaker claims.

Some persona users don’t make claims about their personas’ usefulness or correspondence to reality; they simply say that personas might be helpful for inspiration for some people or teams. We take no issue with that, as long as they don’t forget those caveats and reify the persona. Unfortunately it is probably very difficult for people to read a persona and not think that it describes a user group.

We’ve recently published empirical work on (quasi-)persona prevalence using several large datasets, demonstrating that once a description has more than a few attributes it describes few if any actual people. I’ll put that paper up as soon as I get reprint permission. (If you have access to HFES archives, it is “Quantitative Evaluation of Personas as Information”, Christopher N. Chapman, Edwin Love, Russell P. Milham, Paul ElRif, James L. Alford, from HFES conference 2008, New York.)

What should one do instead of personas? I advocate stronger empirical methods that have more demonstrable validity.