 The index problem arises primarily because the goods and services to be distributed need to be measured if they are going to be distributed according to some pattern (such as equality). The strict equality principle stated above says that there should be ‘the same level of material goods and services’. The problem is how to specify and measure levels. The simplest way of solving the index problem in the strict equality case is to specify that everyone should have the same bundle of material goods and services rather than the same level (so everyone would have 4 oranges, 6 apples, 1 bike, etc.). The problem with adopting this simple solution is that there will be many other allocations of material goods and services which will make some people better off without making anybody else worse off. Such allocations are what are called ‘Pareto superior’ allocations (see  equality  for a more detailed discussion of Pareto efficiency). For instance, someone who prefers apples to oranges will be better off if she swaps some of her oranges for some of the apples belonging to a person who prefers oranges. That way, they are both better off and no one is worse off. Indeed, since most everyone will wish to trade something, requiring identical equal bundles will make virtually everybody worse off than they would be under an alternative allocation. So specifying that everybody must have the same bundle of goods does not seem to be a satisfactory way of solving the index problem. Some index for measuring the value of goods and services is required.