Let’s take legal services as an example. Despite the growing importance of technology in delivery, the impact of the Big Four firms’ entry, and the arrival of other alternative providers, 59% of clients say that trust is still one of the two the most important factors driving their choice of firm to work with across the entire buying process (see figure 1). That’s twice as high as the next most important factor, technical expertise (cited by 32% of clients). These two attributes are, of course, interrelated: As Maister pointed out, technical expertise builds trust.

In a world in which organisations are trying to move towards more evidence-based decision-making, the continuing importance of feels like an anachronism. But it’s the inevitable consequence of information asymmetry in the professional services sector. Clients need lawyers’ expertise because they don’t have it themselves, but if they don’t have that expertise themselves, how can they judge whether a lawyer does? What they do is rely on experience, their own and others’ (a recommendation from their personal network is the second most important factor when they reach the point of deciding which legal firms to invite to bid for a given piece of work). Lawyers will always know more about the matter in hand—otherwise, why hire them? Clients, lacking an equivalent level of information have to make decisions based on trust, and trust comes from experience. Trust, you could argue, is important, not because it’s inherently good, but because it’s a substitute for evidence.

The buying process is designed to compensate for clients’ shortfall in expertise by providing relevant evidence of a law firm’s capability. And our research suggests that it does have an impact. When clients reach the stage of evaluating proposals and presentations made by shortlisted firms, the proportion of clients who say that trust is one of the two most important factors influencing their decision falls to just under 50%. Trust is still top, but the gap between it and other factors—technical expertise and the firm’s understanding of the client’s objectives—is much narrower. However, at the point when the final decision around which firm to use is made, the importance of trust shoots back up to 65%, almost the level at the start of the process. The impact evidence has on clients’ purchase decisions is material but short-lived. At the point of greatest stress—the final decision—clients revert back to relying on trust, which in turn relies on prior experience.

I think what’s key here is the extent to which the process of buying professional services—I don’t think the pattern described above is unique to the legal sector—can change clients’ minds. Evidence of a firm’s ability to do the work concerned, in the form proposals and presentations, isn’t usually powerful enough by itself to counteract clients’ experience. Law firms seeking to break ground with new clients need to provide, not just evidence of their capabilities (thought leadership, for example), but give clients a sense of what it’s like to work with them. They need to provide a better, different, and ultimately memorable experience via their face-to-face meetings and other in-person activities.