Decoding the Time–Cost Trade-Off: Early-Stage Insights from Earned Value Management in Infrastructure Projects

Abstract

Road and drainage infrastructure projects frequently face intense schedule pressures that can influence cost efficiency, particularly during early execution stages. This study aims to evaluate the early-stage schedule and cost performance of a road and drainage improvement project in Karangan Hilir, East Kutai Regency, using the Earned Value Management (EVM) approach. A quantitative descriptive case study method was applied, utilizing project planning documents, weekly progress reports, and cost data for Month 1. Key EVM indicators, including Planned Value (PV), Earned Value (EV), Actual Cost (AC), Schedule Performance Index (SPI), and Cost Performance Index (CPI), were calculated to assess project performance. The results reveal significant schedule acceleration, with SPI values of 2.01 in Week 1 and 3.07 in Week 2, and full physical completion achieved by Week 2 despite planned progress of only 32.59%. However, this acceleration was accompanied by reduced cost efficiency, as indicated by a CPI of 0.95 and a negative Cost Variance reaching −IDR 12,780,056. The S-curve analysis further confirms that actual costs consistently exceeded earned value during the execution period. These findings demonstrate a clear time–cost trade-off, where improved schedule performance is achieved at the expense of higher project costs. The study concludes that while EVM is an effective tool for early detection of performance deviations, project success should be assessed through a balanced consideration of both schedule and cost performance.