such as strikes, boycotts, civil disobedience, and mass protests. A 2016 study found that about a quarter of all cases of democracy protests between 1989 and 2011 lead to democratization. Theories based on political agents and choices Elite-opposition negotiations and contingency Scholars such as Dankwart A. Rustow, and Guillermo O'Donnell and Philippe C. Schmitter in their classic Transitions from Authoritarian Rule: Tentative Conclusions about Uncertain Democracies (1986), argued against the notion that there are structural "big" causes of democratization. These scholars instead emphasize how the democratization process occurs in a more contingent manner that depends on the characteristics and circumstances of the elites who ultimately oversee the shift from authoritarianism to democracy. O'Donnell and Schmitter proposed a strategic choice approach to transitions to democracy that highlighted how they were driven by the decisions of different actors in response to a core set of dilemmas. The analysis centered on the interaction among four actors: the hard-liners and soft-liners who belonged to the incumbent authoritarian regime, and the moderate and radical oppositions against the regime. This book not only became the point of reference for a burgeoning academic literature on democratic transitions, it was also read widely by political activists engaged in actual struggles to achieve democracy. Adam Przeworski, in Democracy and the Market (1991), offered the first analysis of the interaction between rulers and opposition in transitions to democracy using rudimentary game theory. and he emphasizes the interdependence of political and economic transformations. Elite-driven democratization Scholars have argued that processes of democratization may be elite-driven or driven by the authoritarian incumbents as a way for those elites to retain power amid popular demands for representative government. If the costs of repression are higher than the costs of giving away power, authoritarians may opt for democratization and inclusive institutions. According to a 2020 study, authoritarian-led democratization is more likely to lead to lasting democracy in cases when the party strength of the authoritarian incumbent is high. However, Michael Albertus and Victor Menaldo argue that democratizing rules implemented by outgoing authoritarians may distort democracy in favor of the outgoing authoritarian regime and its supporters, resulting in "bad" institutions that are hard to get rid of. According to Michael K. Miller, elite-driven democratization is particularly likely in the wake of major violent shocks (either domestic or international) which provide openings to opposition actors to the authoritarian regime. Dan Slater and Joseph Wong argue that