When talking about lane conditions, you may hear the term ratio. Ratios are meant to let you know how much more oil is in the center of the lane (20 board) than outside (10 board and out).
The figure to the right represents a house pattern. From an ant's eye view, you can see that there is substantially more conditioner in the center of the lane than on the outside boards. This condition allows for a greater amount of friction from the 10 board and out and a generous amount of skid when playing inside the 10 board.
This condition is also very forgiving of a bowler's errors because it allows recovery when missing wide and gives the bowler "hold" when the ball is tugged inside.
Tournament patterns are usually a bit more challenging than a house pattern. The reason is that there is usually less oil in the middle of the lane than on the outside portion. This tends to make the pattern less forgiving by reducing the "tug and swing" room. Most tournaments use approximately a 4 to 1 ratio to put a premium on shot making and adjustments.
USBC has a specific program called Sport Bowling. This program is designed to bring challenging lane conditions to bowlers. Sport requires that the pattern does not exceed a ration of 2.5 to 1. This method of lane conditioning really alters the ball reaction that a bowler may get when bowling on a house pattern. A bowler who pulls the ball inside of target may notice a lot more hook on the inside of the lane and just the opposite for a shot that is sent wide. That shot will tend to hang and not get back to the pocket.
Sport Bowling puts an emphasis on shot making, repeatability, the ability to make adjustments as well as knowing your bowling balls.
Lane conditions are one of the hardest things to master because they are ever changing. With each ball that goes down the lane, conditioner is picked up by the bowling ball. With some of today's high tech equipment, a bowler has to make adjustments at a faster rate. This may also mean that a bowler may need to switch bowling balls in order to accommodate the changing conditions.