He obtained his Ph.D. from the Department of Economics of Yale University in 1982 with the dissertation "Economies of Scale in the Household Production Model and Intra-Family Allocation of Resources".

Notable concepts associated with him are the "Olson ratio"[3] in rent-seeking, egalitarian Nash bargaining solutions,[4] and the debt-adjusted real effective exchange rate.

Fabella, sending a critique to the Philippine Daily Inquirer, criticized the Maharlika Investment Fund bill claiming that it is a "moral hazard arising from unnecessary state intervention and the unjustified economic backdrop".

[6] In a Second International Conference on Agricultural and Rural Development in Southeast Asia (ARD2014) at the Shangri-La Hotel, Makati City, Fabella reported that the Comprehensive Agrarian Reform Program (CARP) met the "opposite" of its goals.

[7] In February 2024, during a roundtable forum at the House of Representatives, Fabella stated that amending the 1987 Philippine Constitution would enhance the country's economic performance.