I picked up this snippet from John Battelle’s Searchblog yesterday:

Marissa Mayer, at Web 2.0 today, shared insights into some lessons Google has learned in trying to serve users. The take-away is that Speed is just about the most important concern of users—more than the ability to get a longer list of results, and more valuable than highly interactive ajax features.

What was most interesting to me, however, was the comments below about how the most effective results from testing were the opposite of what users believed they preferred:

…they didn’t learn that from asking users, just the opposite. The ideal number of results on the first page was an area where self-reported user interests were at odds with their ultimate desires. Though they did want more results, they weren’t willing to pay the price for the trade, the extra time in receiving and reviewing the data. In experiments, each run for about 8 weeks, results pages with 30 (rather than 10) results lowered search traffic (and proportionally ad revenues) by 20 percent.

The reason I wanted to highlight this insight here is that it offers up perhaps one of the greatest challenges across any design practice that tries to focus on the customer experience: what people say they want, and what actually performs best are not necessarily the same. In fact, I would argue that they are different in most cases.

This challenge is not a surprise for professionals in marketing, politics or finance. These fields have long recognized that there is a large difference in what people say they will support vs. what they actually do support. However, it’s a particular challenge in product design because so many people want to “provide the best possible user experience”.

At every company I have worked for, there has always been a large debate about how to do the best product design. Do you reach out, through focus groups and customer visits, and ask your best customers what new improvements they would like to see? Or do you quietly observe, through testing and product metrics, and then use inspired design professionals to produce the great advance in usability?

As a product professional, I truly believe that the answer is to do both. There is no doubt that listening to your customers directly can give you great insight into their experience and their prioritization of problems. This insight is the key to customer empathy, which I believe is the key to customer-centric design in any field.

At the same time, it is extremely important to recognize that the rationalization that many people give when making choices may not be fully informed. They likely do not realize all of the options available to them, or the options that are available technically. They are likely not experts trained in design, finance, marketing, technology, or psychology. Observation, whether direct or indirect, is they key for more informed experts to help produce solutions that the customer may not understand are possible. Customers will ask you for a candle, when what they really want is portable light. They will ask you for a VCR with fast rewind, instead of a DVD player.

So, in this case, to borrow the corporate-speak, you need to embrace the AND. Listen to your customers, empathize with them, know them as they know themselves. But measure and observe, review the data, and leverage the professional expertise of the product team to delight your customer with solutions that they didn’t even realize were possible. Once you have those designs, you have to test and tune them. You’ll know when you are on the right track when you find yourself surprised and delighted by your customer insights and design results.