Runs are the volume of crude a refinery processes, usually reported as barrels per day and as utilisation, which is runs as a percentage of nameplate capacity. Runs are the most direct measure of crude demand there is: every barrel run is a barrel of demand realised, unlike an inventory change which is demand deferred.
Utilisation is the comparable number across regions and time, but it has a trap. Nameplate capacity is a stated figure that is revised infrequently, so a refinery that has been debottlenecked can report utilisation above 100 percent, and a region whose capacity figure is stale will show utilisation that is systematically wrong in one direction. Utilisation is a ratio of a measured numerator to an administrative denominator.
Runs move for three distinct reasons, and separating them is most of the analysis. Economics: when cracks are strong refiners maximise throughput, and when cracks collapse they cut. Maintenance: planned turnarounds cluster in spring and autumn and remove large blocks of capacity on a schedule that is partially known in advance. Disruption: hurricanes, power failures, fires and unplanned outages remove capacity without warning.
The interpretation of a run cut therefore depends entirely on which of the three it is. An economically driven cut is the market working: margins were too thin, so throughput fell. A maintenance cut is a scheduled non-event. An unplanned outage is a genuine supply shock to the product market and simultaneously a demand shock to the crude market, which is why crude and products can move in opposite directions on the same news.