A Design Continuum from Functional to Desirable

Investing in better design has always been a tough sell to non-believers, in part because there aren't enough clear and easy ways to show different levels of design attention.  Here is one method I have used recently:

This chart shows the adoptability of a product based on where it sits on a continuum from Functional to Usable to Desirable.  Rough descriptions of each are:

• Functional = A user can finish what someone could describe as a functional task but doesn't necessarily meet their needs or goals as a user.
• Usable = A user can meet needs and goals without frustration.
• Desirable = The satisfaction of needs and goals is done in such a way that a user builds a positive emotional association with the product (i.e. positive product equity).

Adoptability in the software world is a measure of whether or not people who have bought the product are actively using it.  In other words, is it used or is it shelfware?  Being used doesn't just mean higher support costs… it means that a customer is actually getting value and associating that benefit with the product and the brand.

What this shows on the lower right side is that yes, there are software products that can be adopted that are almost purely functional if they provide a huge amount of relative value.  However, even if they are adopted in a temporary fashion, the negative product equity associated with them means that they are easily and enthusiastically displaced by competitors.  The dot shows a product that moves from no adoption, to adoption with negative product equity, to adoption with positive product equity.

Desirability Testing

One interesting implication of this is that software companies should do all three types of testing in order to drive the proper behavior in valuing each:  Functional Testing, Usability Testing, and Desirability Testing.  Desirability Testing doesn't really yet exist in any formal sense, so this is a good area for further research and experimentation.

Product Equity

Product equity is like brand equity but focused just on the product and not the overall brand experience.  The impact of positive product equity is that customers will continue to use the product in the face of competitive alternatives and will buy additional products from the same vendor.

Are there other methods you have used or seen to meet the same goal of communicating different levels of design attention?

Comments

[Tom Humbarger]

Dave - thanks for the great post and I like your idea of Desirability Testing.

I summarized your comments in a related blog post on my Catalyze blog - http://www.mycatalyze.org/Blogs/CatalyzeBlogsCurrentWisdom/tabid/1006/ctl/SIEdit_Entry/mid/2689/EntryID/890/Default.aspx.

[Christopher Fahey]

"Desirability testing" exists. It's called market research. Focus groups are a typical example.

I think you're using the wrong word for it. "Desire" is orthogonal to "satisfaction and delight in usage". One can desire something that is difficult or even unpleasant to use... for example one may choose to use something for the social status it brings, or for the self-image it promotes