If these values are not reported, try to calculate them. Look for tabular or graphic data showing predicted vs actual results for the patient population under investigation. This is particularly important when the a tool uses continuos or multiple risk stratification's. If not, try to Calculate these. Some models, particularly those using regression equations in the final model, require complex calculations or a computer.
Most models employing regression equations in the final form require a computer.
If the decision support tool doesn't categorize patients into meaningful groups, or doesn't does this with adequate accuracy, then the model will not be of help. Based on the above considerations, weigh the risks and benefits of using the rule. This requires consideration of your own, and you patients, values.