How can state capacity be measured?

State capacity refers to the ability of any state to successfully deliver what are generally considered to be public goods and services to its citizens. State capacity is considered by many public policy experts to be the major factor that explains why some countries are rich or developed while other countries remain underdeveloped. Power in numbers Public policy experts may also look into other indicators such as the number of people employed by a certain state to measure its capacity. Some critics, however, caution against the definition of state capacity in terms of the ability of a certain state to collect tax revenues or the number of staff it can hire to deliver essential public goods and services to its citizens. Critics such as U.S. economist Bryan Caplan also point out that state capacity, as defined by the size of the state, is claimed by public policy experts to be the reason behind the success of certain countries without establishing the necessary causal link between the two.