The trial court abused its discretion in excluding an expert’s opinion as to lost profits in ruling on a summary judgment motion. While most of his opinion was speculative, one part dealt with lost profits using a before-and-after method based on 16 months of actual profits earned before the allegedly harmful event. The before-and-after method is an approved way to compute lost profits damages, and a 16-month before period was sufficiently long to allow reasonable extrapolation into the future had the harmful event not occurred.