The debate on money invested in campaigns and its impact on election results has called into question matters such as the quality of democracy and the efficiency of the elections as a mechanism of citizen control. Campaign financing is a central variable when evaluating its success; therefore, the manner in which it is measured affects the conclusions reached regarding its effects on the results of an election. This article focuses on the Chilean case (more specifically the elections of 2005 and 2009) to analyze the two most common methods to measure campaign spending and suggest as well a third method to better estimate its effects. This methodological contribution complements and refines the current knowledge on the manner in which the expenditure during a campaign affects the election results, while opening a new line of investigation that allows the assessment of other aspects in the dynamic that links campaign financing with electoral performance. We suggest that the way to proceed shall focus on the financial inspection of the actual expenditure without reducing the limits to the expenditure reported.