Hegstad’s main research has been within the field of systematic theology/dogmatics (theological epistemology and ecclesiology) and within the field of empirical research on church and religion. He has been especially active in congregational studies, and is presently working on questions related to church organization and congregational development.
Courses on church organization and development, church sociology and sociology of religion. Courses on ecclesiology and spirituality.
Folkekirke og trosfellesskap. Et kirkesosiologisk og ekklesiologisk grunnproblem belyst gjennom en undersøkelse av tre norske lokalmenigheter, KIFO Perspektiv 1, Trondheim: Tapir forlag 1996 (“Folk church and community of faith. A fundamental problem for church sociology and ecclesiology investigated through an empirical study …”)
Kirke i forandring. Fellesskap, tilhørighet og mangfold i Den norske kirke, Luther forlag, Oslo: 1999 (“Church in transition. Community, belonging and plurality in the Church of Norway”).
“A Minority within the Majority. A Norwegian case study on the Relation between the Church as Folk Church and as a Community of Believers,” Studia Theologica 53 (1999): 119–131.
“Evangelical Movements and Churches in the Nordic countries in a Historical and Contemporary Perspective,” l’Observatoire des religions en Suisse: Les Dynamiques européennes de l’évangélisme. cahier no 2. Université de Lausanne, 2001.
“Hva er menighetsutvikling, og hvorfor behøves det?” Halvårsskrift for praktisk teologi 20 (2003): 4–9 (What is Congregational Development and Why is it Needed?).
“The parish under pressure. New ways of organizing the local church in the Church of Norway,” in The Second International Conference on Church Leadership. Uppsala University, Uppsala, 2005: 47–53.
”Misjonerende folkekirke. Selvmotsigelse eller mulighet?” Norsk Tidsskrift for Misjon 58 (2004): 213–224 (“Missionary Folk Church. Contradiction or Possibility?”).