# Risk Calculator Frequently Asked Questions

### 1) Who should use the ACS NSQIP Risk Calculator? Is this just for surgeons?

The ACS NSQIP Risk Calculator is designed to be used by surgeons, together with their patients, to help inform patients about their individual risks for surgery. There are parts of the ACS NSQIP Risk Calculator that might be hard for patients to understand without their doctor. The ACS NSQIP Risk Calculator does provide a summary report, designed for patients, that they can take home and share with their family, other physicians, and other individuals involved in their care.

### 2) How does the ACS NSQIP Risk Calculator work?

Using the ACS NSQIP Risk Calculator, 20 characteristics about a patient (e.g., type of surgery, age, sex, health information, etc.) can be quickly entered online. These factors are then put into a statistical model in order to predict outcomes for that specific patient. This model is built using data from over 4.3 million operations in the ACS NSQIP database. The result of this model shows that patient’s risk of having any of 18 different complications within the first 30-days following surgery. The predicted length of stay is also shown. For more detailed information, see:  ACS NSQIP Risk Calculator publications.

### 3) What if I don’t know the answer to one of the patient predictors?

The ACS NSQIP Risk Calculator will provide the most precise risk information when all of the pre-operative predictor information is put in. However, if you do not know the answer to one of the fields, you can definitely leave it in the default setting (usually “No”). The model will estimate the risks based on the available information.

### 4) Why does the ACS NSQIP Risk Calculator only provide risk predictions for the first 30-days after surgery?

The model used by the ACS NSQIP Risk Calculator is based on data from operations collected by hospitals participating in ACS NSQIP. The ACS NSQIP program only collects data on complications for the first 30-days after surgery.

### 5) What if the patient has important risk factors that are not entered into the ACS NSQIP Risk Calculator?

The surgeon can adjust the predicted risk using the “Surgeon Adjustment of Risk” button at the bottom right side of the results screen (Step 3 of 4). This should only be used if the surgeon feels that the patient has significant risk factors for surgery that are not already captured by the predictors that have been entered. This adjustment works by increasing the predicted risk for all outcomes by either 1 or 2 standard deviations.

### 6) Why aren’t all of the NSQIP variables used for the Risk Calculator?

The Universal Risk Calculator does not use every variable collected by NSQIP to predict the risk of complications. In some cases, there will be overlap between the contributions of different variables to risk prediction; for example, the risk associated with operative indication may be mostly accounted for by the primary CPT code, wound class, emergency case status, etc. In other cases, the predictive ability of the 19 included variables is so good that adding an additional variable for risk prediction does not significantly improve the ability of the Risk Calculator to predict risk. Finally, some variables (e.g., laboratory values, transfusion within 72 hours of surgery, etc.) may not be known to the surgeon at the time of informed consent and shared decision making.

### 7) How does the Universal Risk Calculator compare to the other risk calculators from NSQIP?

The current Universal Risk Calculator can be used for any procedure, in most surgical subspecialties, while previously developed NSQIP-based risk calculators can only be used for individual procedures (e.g., colectomy, pancreatectomy, etc.). The Universal Risk Calculator provides risk predictions for more outcomes than previous versions (12 total outcomes). While some of the previous risk calculators were only available to NSQIP hospitals, the Universal Risk Calculator is publicly available. Finally, the accuracy of the Universal Risk Calculator is very similar to previously developed, procedure specific risk calculators. For data on detailed comparisons, see:  ACS NSQIP Risk Calculator publications.