Cascade Network Effects and International Policy Diffusion
Information cascades have important implications for international policy diffusion. The theory of international policy diffusion has attributed the reason for the spread of certain policies to different countries to different causes – while some simply cite the success of a policy as the reason for its spread to other countries, others claim it is due to other less objective measures, one being a perceived validity of a policy due to its existing popularity. This effect is often connected to the middle accelerating section of the S curve that is known to model the spread of international policy diffusion. This effect is described by Weyland’s 2005 piece entitled Theories of Policy Diffusion: Lessons from Latin American Pension Reform. After the policy shows some signs of success, and spreads to some other countries, it tends to have an explosion of popularity where many other countries pass similar versions of the bill in a somewhat short timeframe. Additionally, the spread tends to follow a geographic pattern, where countries that have more exposure and geographic proximity to the origin country pass the mimic bill sooner.
The diffusion of a bill thus can likely be modeled with a network cascade effect, where a policy, choice A, spreads to its neighboring nodes first if the q, or perceived benefit of choice A, is low enough, and then spreads more rapidly as more countries pass the bill in a highly connected system such as the global network we have today. Policies often spread through trade agreements or market pressure, thus emphasizing the role of strong ties to the spread of this policy. However, these policies often spread beyond the geographic region of the origin country and spread to other geographic regions over a longer period, thus indicating that weak links and bridges still can carry the policy change, also indicating a lower q value, and a higher a value, the perceived benefit of passing the policy. These network cascades can shed light on the mechanisms of policy diffusion, and how much international interconnectedness and perception of a benefit of a certain policy play in this historic but evolving pattern in international politics.
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