Journal of Informatics Development
Vol. 5 No. 1 (2026): Oktober 2026

Cluster Analysis of Alumni Job Waiting Times Using the K-Means Algorithm with Elbow and Silhouette Methods

Abdur Ro’uf (Institut Teknologi dan Bisnis Widya Gama Lumajang)
Hasyim Asy’ari (Institut Teknologi dan Bisnis Widya Gama Lumajang)
Maysas Yafi Urrochman (Institut Teknologi dan Bisnis Widya Gama Lumajang)



Article Info

Publish Date
01 Oct 2026

Abstract

Evaluating graduate employability is a key indicator for assessing the quality of higher education institutions. One effective approach involves analyzing alumni tracer study data using data mining techniques. This study aims to categorize alumni data based on the waiting period for employment after graduation using the K-Means algorithm. To determine the optimal number of clusters, two methods were employed: the Elbow method (Sum of Squared Errors/SSE) and the Silhouette Score. The research process included data preprocessing—comprising data selection, transformation, and normalization—to enhance data quality prior to clustering. Test results indicated that the Elbow method yielded an optimal cluster count of k=4, whereas the Silhouette method showed the best result at k=3, with a score of 0.62. Consequently, k=3 was selected as the optimal number of clusters due to superior cluster quality. The clustering results revealed that the majority of alumni (67.6%) experienced a short waiting period (averaging ±2 months), while 16.5% faced a long waiting period (±8 months), and 15.9% fell into the medium category (±5 months). These findings are expected to serve as a basis for higher education institutions to evaluate and improve graduate quality, ensuring better alignment with the demands of the job market.

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Journal Info

Abbrev

jid

Publisher

Subject

Computer Science & IT

Description

Focus and Scope Journal of Informatics Development cover all topics under the fields of Informatics, Information System, Information Technology, Computer Science, and Computer Engineering. Informatics and Information system IT Audit Software Engineering Big Data and Data Mining Internet Of Thing ...