Breaking down the question
The question has two distinct halves, and a strong answer must give each its due weight. The first verb is list — enumerate the sources of power, the bases from which some actors are able to secure compliance from others. The second and more demanding verb is explain — set out the indicators by which the presence and distribution of power can actually be measured in a community or society.
The pairing is deliberate. Power is notoriously difficult to observe directly; it is a capacity rather than a visible thing. So the examiner is testing whether you can distinguish the origins of power from the methods sociologists use to detect and gauge it. The measurement half connects to the celebrated community power debate — Hunter's reputational approach, Dahl's decisional approach, and the critiques of Bachrach and Baratz and of Lukes. A script that lists sources but ignores measurement, or that measures without naming this debate, forfeits the marks that separate a good answer from an average one.
A working definition frames the whole. Following Max Weber, power is the probability that an actor within a social relationship will be in a position to carry out his own will despite resistance. The rest of the answer explains where that probability comes from and how it can be assessed.
How to approach it
Organise the answer in three movements. First, a crisp Weberian definition. Second, a structured catalogue of the sources of power. Third — the heavier section — an explained account of the indicators or methods of measurement, built around the community power studies.
For the sources, avoid a flat list. Group them so the answer reads analytically: coercive or physical bases, economic bases, normative or authority bases, and organisational or ideological bases. Draw on Weber's class–status–party, Bertrand Russell's forms of power, and Galbraith's instruments of power to show command of the literature.
For measurement, move through the positional, reputational and decisional indicators, then show how Bachrach and Baratz and Steven Lukes exposed their limits by pointing to non-decisions and the shaping of preferences. The institutional context is developed in our notes on power, elites and political institutions.
Model answer
Power, in Weber's classic formulation, is the capacity to realise one's will even against the resistance of others. It is a relational and unequally distributed capacity, and sociology asks two questions about it — from what does it spring, and how can we tell who has how much of it.
Sources of power
The most elemental source is force and coercion — command over the means of violence. The ability to inflict physical harm, whether through arms, police or organised muscle, underlies the state's monopoly of legitimate violence and much informal domination as well.
A second major source is economic resources. Ownership of the means of production, land, capital and wealth confers the ability to reward and to withhold. In Weber's scheme this is the basis of class power; Galbraith called it compensatory power, the purchase of submission.
A third source is authority and legitimacy — power that is accepted as rightful. Weber distinguished traditional, charismatic and rational-legal authority. Where domination is clothed in legitimacy, compliance flows from duty rather than fear, making this the most stable and economical source of all.
A fourth source is knowledge, expertise and information. In complex societies the technocrat, the professional and the bureaucrat wield power through monopoly of specialised knowledge, a base that grows as societies become more technical.
A fifth source is numbers and organisation. Weber's party rests here — the disciplined mobilisation of many. Trade unions, movements and political machines convert sheer numbers, when organised, into effective power; the unorganised many remain powerless.
A sixth source is ideology and control of ideas. The capacity to shape beliefs, values and what people take to be legitimate — Galbraith's conditioned power — allows domination to be reproduced through consent. Bertrand Russell similarly identified power over opinion as the most fundamental form, since it moulds the other kinds.
Charisma, status and prestige round out the list, showing that power draws on personality and honour as well as on force and property.
Indicators for measuring power
Because power is a capacity and often exercised invisibly, sociologists have devised several indicators to measure its distribution, especially in the community power studies of the mid-twentieth century.
The positional indicator infers power from the formal offices people hold. One maps the commanding positions in government, corporations and institutions and treats their occupants as the powerful. C. Wright Mills used this approach in The Power Elite. Its weakness is that formal office and real influence do not always coincide.
The reputational indicator measures power by reputation. Floyd Hunter, studying Atlanta, asked knowledgeable informants to name those they considered most influential, then traced the interconnections among them. He concluded that a small business-led elite ruled behind the scenes. The method captures perceived influence but risks recording reputation rather than exercised power.
The decision-making indicator measures power by tracing who actually prevails in concrete decisions. Robert Dahl, in Who Governs?, examined key decisions in New Haven and found different actors dominant in different issue-areas, concluding that power was pluralistic and dispersed rather than concentrated. This behavioural test observes power in action, but only where open conflict occurs.
The pluralist confidence in decisions was then challenged. Bachrach and Baratz argued for a non-decision indicator — the second face of power lies in preventing issues from ever reaching the agenda, so that the powerful win by keeping conflict submerged. Measuring power thus requires attending to what is kept off the table, not only to visible contests.
Steven Lukes pushed further with a third-dimensional indicator: the deepest power shapes the very wants and perceptions of the subordinate, so that no grievance is even felt. Since this power operates through consent and works best when invisible, it cannot be measured by observing decisions at all, only by contrasting real interests with expressed preferences.
Assessment
The sources and indicators are linked: coercive and economic power surface in decisional measures, while ideological power is caught only by Lukes's third dimension. No single indicator is sufficient. A rounded assessment of power in any society must combine positional, reputational and decisional evidence, and remain alert to non-decisions and to the moulding of preferences that the crude measures miss.
Examiner's perspective
Examiners reward candidates who honour both halves of the question and keep them balanced. Weak scripts pour everything into a list of sources and treat measurement as an afterthought, or vice versa. The discriminating answer explains the indicators through the community power debate — Hunter's reputational study, Dahl's decisional pluralism, and the Bachrach–Baratz and Lukes critiques — showing that measuring power is itself a theoretical problem.
Three moves lift the answer. First, an explicit Weberian definition that frames both sources and indicators. Second, a grouped rather than random list of sources, enriched by Russell and Galbraith. Third, a closing recognition that the invisible faces of power are the hardest to measure yet often the most decisive. Candidates who convey that measurement is contested, not settled, display exactly the analytical maturity the thirty-mark format demands.