Although construction delays have been subjected to a considerable amount of research, this perennial problem continues to plague the construction industry globally. For this reason, this study contributes to the theory and practice of construction schedule management by identifying the primary delay causes of construction projects and uncovering the underlying factors involved. Following a meta-analysis of 52 common causes of delay identified from the literature review, 20 highly-cited causes are categorised under client-, contractor-, consultant-, labour and equipment-, material- and others-related. A field survey was employed to acquire the views of 148 Malaysian construction practitioners from client, consultant and contractor organisations. These causes are prioritised according to an importance index that integrates both frequency and severity indices, identifying the five leading causes as lack of proper planning and scheduling, too many change orders by clients, lack of competent site management and supervision, lack of competent sub-contractors and financial problems of contractors. Spearman's rank correlation tests reveal a good consensus between the respondent groups to further corroborate the findings. A factor analysis identifies the five principal managerial capabilities influencing schedule delays to be competency management, communication and coordination management, financial management, risk management and site management. These findings are helpful for the praxis of critical reflection in the planning and management of production in construction. This study provides the international construction community with valuable insights to revaluate delay factors and realign project management strategies to ensure the timely delivery of projects.