The level of economic development attained, the form of political organisations, and historical tradition’ are the main variables to define planning systems (Friedmann, 1967, 33 ) shape the evolution of national planning systems’.Earlier events shape later ones or ‘History matters’, “social processes that exhibit positive feedback and thus generate branching patterns of historical development”(Sorensen, 2014). Path dependency happens when’ it is often easier or more cost effective to simply continue along an already set path than to create an entirely new one.

‘Concept of  ‘path dependence’ is that ‘once established some institutions tend to become increasingly difficult to change over time, and so small choices early on can have significant long-term impacts.’ when a particular policy helps to generate a political coalition that works towards the continuation of the policy. (Sorsen, 2014)The longer the period of time, the more people will be invested in it, and the greater each individual’s incentive in ensuring it continues (positive feedback).

‘Important urban examples are restrictive residential zoning that is understood to protect property values, or greenbelts and green-space designation that guarantee landscape amenities. The longer such rules are in place, the more entrenched their status in many cases.’ (Sorensen,2014)Claims of path dependence must provide other alternatives, and have the ability to explain the positive feedback impacts  for continuity. An example of political and policy processes is’ identifying those who benefit from a particular institution, and who support continuation or will fight a change that will disadvantage them’.

(Sorensen, 2014)Alternatively, Path dependence is an organizing concept, a way to narrow conceptually the choice set and link decision through time. It is an appealing concept for understanding public policy development; it provides a label for the empirical observations and intuitions that policies, once established, can be difficult to change or reform. (kay,2005) the origins of path dependence lie in the social sciences and economics.(Booth, 2011)Path dependency is a useful way to understand why certain trajectories were preferred, also examine the possibility of policy transfer and making useful comparisons. ‘Cities are dense collections of institutions’. Sorensen defines institutions as “collectively enforced expectations with respect to the creation, management, and use of urban space”. ‘collective enforcement’ refers primarily to the use of coercion by the state to enforce laws and bylaws, and recourse of private actors to the courts to enforce contracts.Taylor shows an analytic distinction between formal and informal institutions, ideas and structures.

For new institutionalists, formal organisational structures, laws and decision rules are distinguished from informal norms and conventions, and both are distinguished from ideas and macrostructural variables (Hall and Taylor, 1996; Hay, 2008; Pontusson, 1995). Historical institutionalism in political science and political economy tends to be polity-centred; the focus is on governing institutions and the formalised rules and informal conventions associated with them.In many countries new planning systems were established, approaches were institutionalized in different ways in each country or city.

Depending on factors such as their ‘stage of economic and technical development’, the division of power between local, state and central governments, constitutional protections and traditions of property rights, and type of urban system’ different countries and cities made quite varied institutional choices. (Soresen, 2014). Similarly, Taylor points out the notion of complementarity to provide an understanding of ‘policy diffusion and institutional transplantation’, he states that not all forms and practices are possible in all contexts.

 Taylor(2013, p.692) mentions an example of ‘Increasing returns’ or ‘positive feedback’ is the institutionalisation of the welfare state. “As it was not simply the product of  changing political attitudes or cultures. The beneficiaries of welfare state policies have not only defended particular institutions and policies at the ballot box and in the streets, but they also represent a reorientation of societal norms and attitudes in relation to state intervention.”