12.03.2014 Views

The Effects of Sanction Intensity on Criminal Conduct - JDAI Helpdesk

The Effects of Sanction Intensity on Criminal Conduct - JDAI Helpdesk

The Effects of Sanction Intensity on Criminal Conduct - JDAI Helpdesk

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

Appendix J: Sensitivity, Specificity, and Predictive Value<br />

Outcome<br />

No Serious Offense Serious Offense<br />

Predicted Low Risk True Positive (TP) False Positive (FP)<br />

Predicted N<strong>on</strong>-Low Risk False Negative (FN) True Negative (TN)<br />

Sensitivity (Sn)<br />

Specificity (Sp)<br />

Positive Predictive Value<br />

(PPV)<br />

Negative Predictive Value<br />

(NPV)<br />

Sensitivity<br />

<str<strong>on</strong>g>The</str<strong>on</strong>g> proporti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> true positives (predicted/actual low-risk) identified by the model.<br />

Sn =<br />

# TP<br />

#TP+# FN<br />

Specificity<br />

!<br />

<str<strong>on</strong>g>The</str<strong>on</strong>g> proporti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> true negatives (predicted/actual n<strong>on</strong>-low risk) identified by the model.<br />

Sp =<br />

# TN<br />

# TN+# FP<br />

Positive predictive value<br />

!<br />

<str<strong>on</strong>g>The</str<strong>on</strong>g> proporti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> predicted low-risk cases that are actually low risk (no serious <str<strong>on</strong>g>of</str<strong>on</strong>g>fense).<br />

PPV =<br />

#TP<br />

# TP+# FP<br />

Negative predictive value<br />

!<br />

<str<strong>on</strong>g>The</str<strong>on</strong>g> proporti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> predicted n<strong>on</strong>-low risk cases that are actually n<strong>on</strong>-low risk (commit<br />

serious <str<strong>on</strong>g>of</str<strong>on</strong>g>fense).<br />

NPV =<br />

#TN<br />

#TN+# FN<br />

!<br />

233

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!