Individual observations (I-CHART)

The I-CHART is another variables control chart used to monitor individual observations (samples of one each) rather than larger samples.   The I-CHART is most used in cases where a considerable period of time elapses between opportunities to collect quality observations.  For example, there only be one quality observation per shift in operations with long lead times.  Although the I-CHART is usually identified with manufacturing applications, it is widely used in casinos to monitor card, dice, and roulette games.  The individual observations entered in the chart are typically the net cash profits recorded when a dealer settles his or her account with the house at the end of a work period.