When a government agency in Spain issues a request for proposals, it states the maximum amount it is willing to pay for the service or product. The "baja" is the discount on that maximum amount that a bidder is willing to offer. The "baja media" is the average of the "bajas" and is a measure of how "hungry" the industry is. For example, in times of little work, bidders will cut each others' throats to get a job, so the "baja media" will be large.