These reputations affect how many brainstorms designers are invited to and how many they turn down.
So another answer to the "effectiveness at what" question is that brainstorms create a social arena in which status auctions occur.
Qualitative and survey data in Table 1 indicate that brainstorms were fun and impressive for clients and helped "hook" them for long-term projects.
First, brainstorms are an efficient way for clients to explain their design problems and gather ideas from others.
Numerous experiments show that face-to-face brainstorms are more efficient than nominal groups for gathering ideas from others.
Hearing ideas at several times the rate of one-on-one conversations may help explain why IDEO's brainstorms impress clients.
Clients, like others at IDEO brainstorms, are taught to praise ideas, build on suggested ideas, be playful, wait their turn before talking, and not be critical.
So when clients express positive emotions and opinions about IDEO's designers and their ideas during brainstorms, they may then align their private beliefs to match their public behavior, regardless of prior beliefs.
These forces help explain why clients who attend brainstorms may view them as a more efficient way for gathering ideas and react more positively than if they had a series of one-on-one meetings with designers.
But, as Table 1 indicates, people at IDEO viewed brainstorms as a useful income source; 15 to 25 hours of designer time are billed for the "back-to-back" brainstorms usually held at the start of a project, along with time for organizing the meetings and writing the report.
If designers are less efficient at generating ideas in brainstorms than working alone, then clients will be billed for more hours for the same amount of work.