Patient and public involvement managers must distinguish between two sets of people - ordinary members of the community and more expert contributors. Few can be both

Health service managers have had to grapple with successive initiatives on patient and public involvement. Rushed legislation has focused on structures without paying adequate attention to underlying objectives. There are examples of dynamic and successful practice but overall the picture is of muddled and variable implementation.

But if the underlying purpose of involvement was better understood and spelled out, managers would be better equipped to implement current legislation and future policies could be improved.

Managing objectives

Current thinking on public involvement assumes it can achieve multiple objectives, including greater accountability, services that are more patient centred and so on. Each of these is desirable in its own right but different objectives need different structures and processes and even different participants. So it is vital to be explicit about the objective of any such initiative - only then can a reasoned strategy for structure, process and recruiting participants be designed.

The academic literature identifies two distinct rationales for public participation. One is that it is a process of representativeness, with the aim of broad-based, more-or-less democratic representation of a public. For the NHS, that public might be the local community, users of a particular service, or members of a foundation trust. The other rationale understands public participation as a process of expertise, seeking to draw on the knowledge, skills and experiences of particular people.

The two are quite different. The first emphasises democratic accountability. It sees participation as a means of better understanding people's needs and wants and participants must be representative of this group, at least in their life circumstances, outlooks and characteristics. They must be "typical" or "ordinary".

An example of this in action is the Principia Health Network, a social enterprise formed by GPs and community healthcare staff in Nottingham "to share skills and resources to provide better local healthcare". Membership is open to anyone registered with the GP practices. Involvement mechanisms include consultations via electronic mailing list and discussion boards and meetings open to all residents.

The second, expertise based, concept requires rather different participants; those who have a more proactive, knowledge based contribution to make on account of their professional or personal skills, or particular experience of a service.

Know your public

The Choice project at the former Dartford, Gravesham and Swanley primary care trust (now part of West Kent PCT) has an explicitly knowledge based aim, bringing users and carers into contact with practitioners to "explore service improvements and education programmes that can benefit people with osteoporosis". This led to the development of audits, screening and assessment tools, information leaflets and publicity events.

Sometimes involvement can meet both objectives. Representatives of a wider population may also make knowledge based contributions. But the different rationales require different recruitment methods.

Current NHS policies allude to both, without attending to the potential contradictions. For example, recent Department of Health guidance (Strengthening Accountability: involving patients and the public) emphasises the need for "a representative cross-section of people, community groups and key stakeholders [to] have been involved from an early stage". Elsewhere in the same document representativeness is played down; instead the need is to draw on "knowledge, experience… and considered and informed opinions".

Local improvement network policy is similarly clouded. Our Health, Our Care, Our Say calls for informed patients and user groups to help improve commissioning, while expecting such involvement to result in a "collective voice" and "a view of health and social care in the round" that is representative of the local community.

We suggest managers involved in public involvement need to take two steps. First, distinguish between representative and knowledge based participation. Second, consciously opt for one or the other.

The NHS Centre for Involvement and Involve, which is funded by the National Institute for Health Research, both suggest a customised approach. But guidance documents produced by these bodies and others would be strengthened if they spelled out the different scenarios and their different implications. Policy makers need to be explicit about which rationale is to be emphasised.