He made a series of important contributions in the study of disparities, redistribution, insurance arrangements and tax systems.
From 1976 to 1980, he was a member of the Petroleum Price Board of the Swedish Government's Economic Commission and, from 1996 to 1997, of the Government Committee on Priorities in Health Care.
He served as chairman of the Government Expert Committee on Investment Policies of the Petroleum Fund in 2004.
Sandmo was affiliated with the SNF, a prominent research firm, he mainly did work on public economics and taxation.
His articles have appeared in many prominent Economic journals.