The Organization of the Petroleum Exporting Countries’ bet that oil demand will steadily rise in 2016 has a looming problem: Consumption is notoriously difficult to predict. Since 2010, the oil market’s three biggest supply-and-demand forecasters—the International Energy Agency, the U.S. Energy Information Administration and OPEC itself—have rarely been accurate in their short-term forecasts of demand growth, a Wall Street Journal analysis found. For instance, in December last year, the EIA predicted oil demand would increase by 900,000 barrels a day in 2015. But in its latest revision it said consumption increased by 1.4 million barrels a day this year. On average, the agencies’ December year-ahead forecasts have missed their later assessments of actual consumption by 600,000 barrels a day since 2010, according to the Journal analysis. The mistaken prognoses highlight the challenges OPEC faces on Friday when the group’s ministers gather in Vienna for a potentially contentious meeting. Some […]