On any one day, three typical questions facing a PSL in, say, a litigation department might be:

Finding answers to the first two questions is simple. Many law firms will have sophisticated systems for managing know how and access to a plethora of commercial online databases. The information should appear at the PSL's fingertips within seconds because it will have been tagged and codified by reference to a complex taxonomy and retrieved by a sophisticated overarching search engine.

The answer to the third question will not be so easy to find electronically. A firm's database may throw up the names of litigators who have appeared before the judge in question. An email to the department may also elicit further names. However, it is unlikely to find anything in writing that sets out how Mr Justice X is likely to react. The most any database can do is to point the fee earner in the direction of experts. The only way to acquire an understanding of Mr Justice X is to speak to the relevant lawyer: a "person to person" solution, rather than a "person to document" solution which provided the answers to the first two questions. This illustrates in a nutshell the difference between explicit and tacit knowledge.

In a law firm or in-house legal department, tacit knowledge consists of the stock of expertise that is neither written nor formally expressed yet is nevertheless essential for its effective operation. Tacit knowledge is an inexact science and is essentially based on skills and experiences. It is knowing how to do something: how to present an agreement effectively, how to handle an aggressive opponent, how to formulate a strategy. Much advice to clients is rooted in lawyers' tacit knowledge and can provide an organisation with a competitive edge.

Although the lines can get blurred, the distinction is important because each type of knowledge requires different management. The means to capture knowledge is dependent on its type. The fact that tacit knowledge is such a slippery and elusive concept does not mean that it is not worth capturing. At a very minimum, an organisation will reap the benefits of not losing its tacit knowledge when the expert in whose head it is located leaves.

The challenge is how to capture it. How can you create an infrastructure where tacit knowledge is readily accessible? Can it be converted into explicit knowledge?

Since the "person to person" approach works best in relation to tacit knowledge, at the very least, there must be a system that allows lawyers to locate the experts. Many law firms have specialisation directories that set out their lawyers' expertise and previous experience. They may also have directories of experts, arbitrators, barristers and mediators. Electronic yellow pages are a very useful starting point. Data protection issues, however, should not be ignored in relation to directories of external experts.

A collaborative culture is crucial. A "closed door" culture will do little to encourage interaction but an environment of interactive collaboration will do much to facilitate the transmission of tacit know how. A mixture of formal and informal collaboration can be encouraged through meetings (at departmental and at team level), working on joint projects, away days, coffee machine conversations, canteen discussions, brainstorming sessions, and debriefings at the end of a project. Training workshops and seminars are also useful tools for extracting knowledge otherwise locked in peoples' heads.

Old fashioned methods of information transmission, such as the trainee system or mentoring, are effective media for the transmission of tacit knowledge. They also ensure that it is not concentrated in only one person.

Communities of practice also assist. They can be either informal or formalised in teams. Communities of practice can exist within a department, across departments or even across jurisdictions in the case of a global law firm. For example, in the litigation department there could be a community of practice that specialises in mediation. Via regular meetings, mediation know how can be transmitted among group members, communities of practice can help drive strategy, solve problems quickly, transfer best practices and develop new skills.

Information technology (IT) has acted as a catalyst for the knowledge management (KM) movement yet it would be a mistake to see KM purely in terms of IT. IT is both an enabler and a disabler. While most IT-supported KM initiatives have been geared towards the transmission of explicit knowledge, there are certain tools that will help in the transmission of tacit knowledge. In addition to the specialist databases mentioned above, video conferencing (where people can learn by observation), email, intranet based discussion groups, extranets and, of course, the telephone are all useful tools for linking people and promoting discussion and exchange of information. Expert locating technology is another tool that is beginning to be marketed. Yet there are many pitfalls and limitations in using IT for KM purposes: trying to force fluid knowledge into rigid data structures or focusing too much on the system at the expense of content are just two examples. It is a cliché to say that KM is more than the sum of its IT applications.

Creating and sharing tacit knowledge are essentially social activities. This knowledge represents a valuable intellectual resource that cannot easily be duplicated by competitors. Tacit knowledge must be converted into explicit knowledge so that it can be recorded. But recorded knowledge represents what a particular person knew at a particular time, so it is static and can soon become outdated. An innovative law firm establishes an atmosphere where knowledge is continuously created, captured and disseminated. At Allen & Overy, we have a collection of guides known as Fountain Guides that make the tacit explicit. These guides, which are global practice manuals, codify legal knowledge and transaction/case management experience and are meticulously updated by PSLs to reflect new developments and experiences. They are not the product of one person but represent the collective know how of the partners and senior associates who specialise in that area.

You can, of course, go too far in your quest for capturing all forms of knowledge. "Analysis paralysis" is a common syndrome, as is over-intellectualising the problem. In the end, each organisation must solve the problem for itself. If the knowledge cannot be converted into action, the most sophisticated KM system is redundant.