Overstay2 scoring model for St. Boniface
This page describes the Overstay2 scoring model for St. Boniface for the Project Overstay2, one of the site-based Overstay2 scoring models. The model and the Data definition for factor candidates for the Overstay2 project it uses were developed in Re-analysis and generation of Overstay2 model and is used to generate the Overstay2 colour, which in turn drives the Overstay2 processes on the units to reduce discharge delay.
Data elements and assigned coefficients
The binary logistic regression Y (Overstay GE 10 Days) which gave the AUC C-index =0.771 implying better predicted model and Hosmer and Lemeshow Goodness of fit test Chi-Square value of 11.1321 (prob=0.133) is :
LN(OS/1-OS) = Y
Y = Intercept Estimate + sum of all the rest of (the Parameter values multiplied by the Estimate) listed below:
| Parameter | Estimate | Prob > ChiSq |
|---|---|---|
| Intercept | -7.308524846 | <.0001 |
| Homeless | 1.012402498 | 0.0087 |
| Dementia | 0.570758477 | 0.0081 |
| MI | 0.456135105 | 0.0067 |
| Diabetes | -0.527659475 | 0.0068 |
| GCS_Motor | 0.416028616 | 0.0323 |
| ADL_bath | 0.412497217 | <.0001 |
| ADL_dress | -0.19051492 | 0.0034 |
| ADL_continence | 0.181464804 | <.0001 |
| ADL_Adlmean_nh | -0.059389318 | 0.0013 |
Where OS is the likelihood to overstay 10 days and beyond.
How to calculate OS:
- OS = exp(Y) / (1 + exp(Y)
- The model gave a 0.028 optimum cut-off probability for OS GE 10 Days with sensitivity = 69.0%, the rate of identifying OS GE 10d out of the patients who actually have OS GE 10d and with specificity = 70.4 the rate of identifying OS LT 10d out of the patients who actually have OS LT 10d. This cut-off point of 0.028 will result to 29.6% rate of identifying OS GE 10d out of the patients who actually have OS LT 10d. Increasing the cut off predicted probability of (Overstay >= 10 days) to 0.039 resulted to sensitivity = 66.9%, thus reducing the rate of identifying OS GE 10d out of the patients who actually have OS LT 10d to 26.3%. Thus a predicted probability of (Overstay >= 10 days) of 0.039 is going to be used to classify patients into two groups; Overstay >= 10 days and Overstay < 10 days. See more discussion on Overstay2 colour.
- The model has been validated using the data from the validation set of same period. The AUC C-index = 0.742, the Hosmer and Lemeshow Goodness of fit test Chi-Square value = 13.4047 (prob=0.099) and the optimum cut-off probability for OS = 0.028 with sensitivity = 67.1% and specificity = 71.6%.
Model files
- files describing the model and records of discussion about it are at
S:\MED\MED_CCMED\Julie\MedProjects\Overstay_Project_2025\3_HSCSTB_15Oct2025\STB\STB_FinalModel
Log
- 2025-06-09 no work yet
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