Joel W. Johnson, "Incumbents Without a Campaign Finance Advantage: Competition and Money in Chile's Congressional Elections." Journal of Politics in Latin America 3, 3 (2011): 3-33.
Abstract (full article is ungated)
Research from various countries has shown that incumbents in legislative elections raise and spend more money when they face a tougher contest. A statistical analysis of Chilean candidates’ campaign finance disclosures shows the opposite: an inverse relationship between incumbent spending and electoral competitiveness. This occurs because Chile’s deputies are relatively limited in their influence over policy and pork and because the congressional electoral system makes most competitive contests relevant only to the intra-coalitional balance of power. This account implies that political finance is as much a function of political systems and the supply of contributions as it is candidates’ demand for funds, and motivates several hypotheses about campaign finance in Chile. Among others, the analysis confirms that incumbents and challengers compete on a level playing field, spending similar amounts of campaign finance. The paper also illustrates that incumbents and challengers fare equally well in Chile’s “secret” donation system.
There is a glass half full/glass half empty vibe here. It's good that incumbents can't vacuum up enormous amounts of money that give them a large advantage against challengers.
The reason for this, though, is that the Chilean legislature is weak. I learned this early on when studying civil-military relations. The military budget is really out of legislative hands, and defense policy comes from the military and the executive branch. Without much power over money, members of Congress can't help special interests, which then have little incentive to give them contributions.
It's notable that although the electoral system is changing in Chile, the essential role of the legislature is not. Coalitional dynamics might change, but members will still lack the power of pork.