Analisis Stabilitas Indeks Kemahalan Konstruksi (IKK) sebagai Indikator Pendukung Pertumbuhan Ekonomi Daerah di Provinsi Sumatera Utara Tahun 2020–2024 Menggunakan Statistical Quality Control

Abstract

Background: The Construction Cost Index (IKK) is a key indicator that reflects the efficiency of infrastructure development costs in a region. Instability in IKK values over time may lead to inaccurate allocation of development budgets. Objective: This study aims to analyze the stability of IKK values in districts/cities of North Sumatra Province during 2020–2024, and evaluate its role as a supporting indicator of regional economic growth. Methods: IKK data were obtained from the Central Statistics Agency (BPS) for 33 districts/cities. The analysis used the Statistical Quality Control (SQC) method with X̄ (mean), R (range), and S (standard deviation) control charts, processed manually in Excel and supported by SPSS software. Results: Most IKK values fall within statistical control limits. Only a few regions, such as Nias, Nias Selatan, Nias Barat, and Gunungsitoli, exceeded the upper control limit in the X̄ chart. The R and S charts showed no significant deviations, indicating that the IKK measurement process is statistically stable. Conclusion: The reporting and development process of IKK over the five-year period is considered stable. IKK can be reliably used to support regional development planning and control construction costs.