There are differences between the socio-economic development in colonized and non-colonized areas/countries. As Dixon (1999) summarizes for continental Southeast Asia:

„The preservation of a degree of Thai political independence and the consequent less intensive mode of assimilation that resulted almost certainly ensured a slower pace of change compared to neighbouring colonial economies. The rapid disruption and disintegration of the traditional social structures that marked French rule in Indo-China and British rule in Burma was largely avoided. To a degree the Thai state could control the rate and path towards the establishment of capitalist production. In the long term the much more gradual development of production and internationalization of the economy probably served the mass of the population well. (...) Rice production remained based on small-scale owner occupied farms without development of large-scale production or foreign landlords as was the case in Burma.“ (Dixon 1999: 57f)

However, the impact of colonialism should not be overestimated. As demonstrated in many analyses, it is one important determinant of the socio-economic development of Africa/Asia in the 19th-20th century, but not the only one and in many cases not the most important one. On the Arab Peninsula, for instance, the decline of the demand for pearls in the 1920s and the large-scale production of petroleum is considered to have changed societies much more than British indirect rule and related investment (Owen/Pamuk 1999: 76ff). Murray (1980) stresses that

“colonies were often annexed before their geopolitical or economic value to the Imperial Empire was even assessed. One consequence was that, once colonies were seized, the imperialist powers were frequently content to permit local economic activities to stagnate rather than to allow a rival metropolitan state administration to assume either formal or informal control. This 'benign neglect' – in addition to the discovery and subsequent exploitation of natural resources in other colonies – produced a heterogenous pattern of capitalist economic development throughout the colonial world.” (Murray 1980: 13)

We conclude that caution is justified regarding the supposedly transformatory effects of colonialism. While for some areas, it is obvious that profound changes in economy and social structure can be traced back to colonial measures, others remained almost untouched, sometimes even conserved. To deal with the impact of colonialism by dummy-variables (“colonized/not-colonized”, French/British etc.) is clearly inadequate. The challenge is to identify the main dimensions of colonial transformation and to find indicators to measure the factual, real levels of impact.