There is a difference between short interest and short volume. Most pennylanders don't understand this.Short volume has nothing to do with shorts covering or opening, a short position.
Short volume is the amount of daily volume which is no cleared/settled at days end.
Short volume Is used by day traders to see when to expect a Broker/dealers cover, before going naked short. Over 30% is strong fails to clear and a daily price pop may happen 3 days after.
Short interest is shareholders betting against positive price action in the underlying stock. Over 10% is strong negative sentiment.
Short interest Is used to determine precentage of float which is held negative. To help swing traders know whether to expect a climb stall fight, by shorts.