| Variable | Calculation |
|---|---|
| Solution priority number (SPN) | SPN = Effectiveness x cost x implementation. |
| Effectiveness | Very effective solution (3). The probability of occurrence can be eliminated or reduced dramatically, or a control measure capable of detecting the error can be installed. |
| Effective solutions (2). The probability of occurrence can be reduced. Despite the reduction there is still significant risk of hazard. Measures capable of detecting the error are not in place. | |
| Ineffective solutions (1). The probability of occurrence cannot be reduced, and measures capable of detecting the error are not in place. | |
| Cost | Low cost (3) can be paid for out of daily operating budget. |
| Moderate cost (2) needs to be paid for out of unit-level budget. | |
| High cost (1) requires payment from hospital-level budget. | |
| Implementation | Easy (3) requires no training. |
| Moderate (2) requires a training course, and some resistance is expected. | |
| Difficult (1) implementation means that a culture change is needed, and strong resistance is expected. |
Note: Godfrey, et al.32 described their scales for effectiveness, cost, and implementation more precisely than that presented here by tightly linking it to hazard scores in the Department of Veterans Affairs Healthcare Failure Modes and Effects Analysis (HFMEA).