The Model describes the Cancer cases in Niger Delta University Teaching Hospital, Bayelsa State, Nigeria
# NDUTH Cancer Survival Policy Scenario App — Version 2
This package contains a standalone HTML/CSS/JavaScript policy dashboard, the
complete R modelling scripts and the bundled synthetic Excel workbook.
## Dynamic scenario interpretation
The Scenario Builder includes a plain-language interpretation box that updates
whenever a slider or dropdown changes. It converts survival percentages into:
- expected patients alive at three years;
- expected patients alive at five years;
- differences from current care;
- projected median-survival change;
- five-year follow-up workload;
- chemotherapy and radiotherapy service implications;
- the operational change needed to achieve the selected early-diagnosis target.
The explanation retains the synthetic-data and non-causal-treatment warnings.
## Model-comparison display
The Model Evidence page now shows the predicted survival curves from all four
candidate AFT distributions:
- Exponential
- Weibull
- Log-normal
- Log-logistic
The chosen model is displayed as a thicker solid line. The other models use
thinner patterned lines. Ranking cards show AIC, delta AIC and BIC, with the
selected model clearly labelled.
## Cox–Snell 45-degree diagnostic
The Model Evidence page also includes Cox–Snell residual curves for all four
candidate AFT models. Each curve is compared with a 45-degree diagonal line.
A well-fitting model should follow this reference line reasonably closely.
The selected Weibull model is displayed as a thicker solid line. Diagnostic
cards report the mean absolute deviation from the diagonal; lower values
indicate closer agreement. The tail is limited at the pooled 95th percentile
of the residuals because goodness-of-fit curves become unstable where very few
patients remain at risk.
This is a 45-degree reference line, not a 45% significance threshold.
## Policy controls
- **Early-stage diagnosis:** slider
- **Treatment pathway:** dropdown
- **Treatment timeliness:** dropdown, displayed as exploratory evide …