Control Chart Selection
The following table can guide you to select the control chart to use depending on the type of data, what you want to track and sample size.
| Data | Type | Tracking | Sample | Charts |
| Variable Data | Individuals | Process level (individuals) | Subgroup size = 1, data point >30 | I Chart |
| Process variation (moving range) | Subgroup size = 1, data point >30 | MR Chart | ||
| Process level and variation | Subgroup size = 1, data point >30 | I-MR Chart | ||
| Subgroups | Process level (means) | 5-10 subgroups | Xbar Chart | |
| Process variation (ranges) | 5-10 subgroups, small subgroups (<= 5) | R Chart | ||
| Process variation (standard deviations) | 5-10 subgroups, large subgroups (<= 5) | S Chart | ||
| Process level and variation | 5-10 subgroups, small subgroups (<= 5) | XBar-R Chart | ||
| Process level and variation | 5-10 subgroups, large subgroups (<= 5) | XBar-S Chart | ||
| Process level and variation | 5-10 subgroups, large subgroups (<= 5) | I-MR-R/S Chart | ||
| Non-weighted | Process level (Minor shifts) | Subgroups >= 1, large samples | MA Chart | |
| Weighted | Process level (Minor shifts) | Subgroups >= 1, large samples | EWMA Chart | |
| Attribute Data | Defectives (Defective product) | Number of defectives | Equal subgroup size | NP Chart |
| Percentage of defectives | Different (or same) subgroup size | P Chart | ||
| Defects (Product can have more than one defect) | Number of defects | Equal subgroup size | C Chart | |
| Number defects per unit | Different (or same) subgroup size | U Chart |