There are, however, few measures of social welfare provision which leave absolutely no-one
worse off - if only because someone, somewhere has to pay for them. The main exceptions
are measures which increase both efficiency and effectiveness. Efficiency depends on the
relationship between aims and costs; the most efficient measure is the one that yields the
best result at least cost, but the constraint of cost means that something less than the
maximum goal may be achieved. Effectiveness depends on maximising the achievement of
goals. Efficiency and effectiveness are sometimes elevated to the status of principles,
because they are the means to increase welfare; but in fact they are secondary to other
principles, because their importance derives from the aims they are serving.