at the national level it is difficult for donors to meet the aid effectiveness principle of aligning their inputs with country priorities if a developing country has not yet established such priorities at the institutional level varying national circumstances or enabling environments can enhance or inhibit an intervention s success eg a regulatory environment s influence on an intervention s ability to mobilise private finance sitespecific environmental factors can also influence the performance of an intervention eg a wind turbine will generate varying amounts of electricity depending on the prevailing wind speed some climate interventions can give rise to immediate results eg energy efficiency projects however some interventions will target results that can only be assessed after an extended period of time eg constructing infrastructure that can withstand a in year flood these different time horizons for the results of an intervention mean that effectiveness levels will vary depending on when results are assessed