|
| 1 | +--- |
| 2 | +title: "Before we Validate Performance" |
| 3 | +author: "Uriah Finkel" |
| 4 | +format: |
| 5 | + html: |
| 6 | + echo: false |
| 7 | +mermaid-format: svg |
| 8 | +--- |
| 9 | + |
| 10 | +Ideally we would like to keep Performance Validation as agnostic as possible. However, the structure of the validation set (`probs`, `reals` and `times`) implies the nature of the related assumptions and the required use case. |
| 11 | + |
| 12 | +So before we validate performance, let us consider the underlying process. |
| 13 | + |
| 14 | +✍️ The User Inputs\ |
| 15 | +🪛 Internal Function |
| 16 | + |
| 17 | +# ✍️ Declare reference groups |
| 18 | + |
| 19 | +The dimentions of the `probs` and the `real` dictionaries imply the nature of the use case: |
| 20 | + |
| 21 | +TODO: copy from rtichoke r README. |
| 22 | + |
| 23 | +##### One Model, One Population: |
| 24 | + |
| 25 | +- Just one reference group: "model". |
| 26 | + |
| 27 | +##### Several Models, One Population: |
| 28 | + |
| 29 | +Compare between different candidate models. - Each model stand as a reference groups such as "thin" model, or a "full" model. |
| 30 | + |
| 31 | +##### Several Models, Several Populations |
| 32 | + |
| 33 | +Compare performance over different sub-populations. - Internal Validation: "test", "val" and "train". - External Validation: "Framingham", "Australia". - Fairness: "Male", "Female". |
| 34 | + |
| 35 | +# ✍️ Declare how to stratify predictions ✂️ |
| 36 | + |
| 37 | +The `stratified_by` argument is designed for the user to choose how to stratify predictions for decision-making, each method implies different problem: |
| 38 | + |
| 39 | +::: {.panel-tabset} |
| 40 | + |
| 41 | +## Probability Threshold |
| 42 | + |
| 43 | +::: {.panel-tabset} |
| 44 | + |
| 45 | +By choosing Probability Threshold as a cutoff the implied assumption is that you are concerned with individual harm or benefit. |
| 46 | + |
| 47 | +### Baseline Strategy: Treat None |
| 48 | + |
| 49 | +```{mermaid} |
| 50 | +
|
| 51 | +graph LR |
| 52 | + subgraph trt[Treatment Decision] |
| 53 | + linkStyle default stroke:#000 |
| 54 | + A("😷") -->|"Treatment 💊"|B("<B>Predicted<br>Positive</B><br>💊<br>😷") |
| 55 | + A -->|"No Treatment"|C("<B>Predicted<br>Negative</B><br>😷") |
| 56 | + end |
| 57 | +
|
| 58 | + subgraph ut[Utility of the Decision] |
| 59 | + subgraph pred[Prediction Model] |
| 60 | + B -->|"Disease 🤢"| D["<B>TP</B><br>💊<br>🤢"] |
| 61 | + B -->|"No Disease 🤨"| E["<B>FP</B><br>💊<br>🤨"] |
| 62 | + C -->|"Disease 🤢"| F["<B>FN</B><br>🤢"] |
| 63 | + C -->|"No Disease 🤨"| G["<B>TN</B><br>🤨"] |
| 64 | + end |
| 65 | + subgraph baselinestrategy[Baseline Strategy: Treat None] |
| 66 | + Dnone["<B>FN</B><br>🤢"] |
| 67 | + Enone["<B>TN</B><br>🤨"] |
| 68 | + Fnone["<B>FN</B><br>🤢"] |
| 69 | + Gnone["<B>TN</B><br>🤨"] |
| 70 | + |
| 71 | + D---Dnone |
| 72 | + E---Enone |
| 73 | + F---Fnone |
| 74 | + G---Gnone |
| 75 | + end |
| 76 | + subgraph nb[Net Benefit] |
| 77 | + Dnb[1] |
| 78 | + Enb["pt / (1-pt)"] |
| 79 | + Fnb[0] |
| 80 | + Gnb[0] |
| 81 | + Dnone---Dnb |
| 82 | + Enone---Enb |
| 83 | + Fnone---Fnb |
| 84 | + Gnone---Gnb |
| 85 | + end |
| 86 | + end |
| 87 | +
|
| 88 | +
|
| 89 | +
|
| 90 | + style A fill:#E8F4FF, stroke:black,color:black |
| 91 | + style B fill:#E8F4FF, stroke:black,color:black |
| 92 | + style C fill:#E8F4FF, stroke:black,color:black |
| 93 | + style D fill:#C0FFC0,stroke:black,color:black |
| 94 | + style Dnone fill:#FFCCE0,stroke:black,color:black |
| 95 | + style Dnb fill: #C0FFC0,stroke:black,color:black |
| 96 | + style E fill: #FFCCE0,stroke:black,color:black |
| 97 | + style Enone fill: #C0FFC0,stroke:black,color:black |
| 98 | + style Enb fill: #FFCCE0,stroke:black,color:black |
| 99 | + style F fill:#FFCCE0,stroke:black,color:black |
| 100 | + style Fnone fill: #FFCCE0,stroke:black,color:black |
| 101 | + style Fnb fill: #E8F4FF,stroke:black,color:black |
| 102 | + style G fill: #C0FFC0,stroke:black,color:black |
| 103 | + style Gnone fill: #C0FFC0,stroke:black,color:black |
| 104 | + style Gnb fill: #E8F4FF,stroke:black,color:black |
| 105 | + style nb fill: #E8F4FF,stroke:black,color:black |
| 106 | + style pred fill: #E8F4FF,stroke:black,color:black |
| 107 | + style baselinestrategy fill: #E8F4FF,stroke:black,color:black |
| 108 | +
|
| 109 | + classDef subgraphStyle fill:#FAF6EC,stroke:#333,stroke-width:1px |
| 110 | + class trt,ut subgraphStyle |
| 111 | +
|
| 112 | +``` |
| 113 | + |
| 114 | +### Baseline Strategy: Treat All |
| 115 | + |
| 116 | +```{mermaid} |
| 117 | +
|
| 118 | +graph LR |
| 119 | + subgraph trt[Treatment Decision] |
| 120 | + linkStyle default stroke:#000 |
| 121 | + A("😷") -->|"Treatment 💊"|B("<B>Predicted<br>Positive</B><br>💊<br>😷") |
| 122 | + A -->|"No Treatment"|C("<B>Predicted<br>Negative</B><br>😷") |
| 123 | + end |
| 124 | +
|
| 125 | + subgraph ut[Utility of the Decision] |
| 126 | + subgraph pred[Prediction Model] |
| 127 | + B -->|"Disease 🤢"| D["<B>TP</B><br>💊<br>🤢"] |
| 128 | + B -->|"No Disease 🤨"| E["<B>FP</B><br>💊<br>🤨"] |
| 129 | + C -->|"Disease 🤢"| F["<B>FN</B><br>🤢"] |
| 130 | + C -->|"No Disease 🤨"| G["<B>TN</B><br>🤨"] |
| 131 | + end |
| 132 | + subgraph baselinestrategy[Baseline Strategy: Treat All] |
| 133 | + Dall["<B>TP</B><br>💊<br>🤢"] |
| 134 | + Eall["<B>FP</B><br>💊<br>🤨"] |
| 135 | + Fall["<B>TP</B><br>💊<br>🤢"] |
| 136 | + Gall["<B>FP</B><br>💊<br>🤨"] |
| 137 | + |
| 138 | + D---Dall |
| 139 | + E---Eall |
| 140 | + F---Fall |
| 141 | + G---Gall |
| 142 | + end |
| 143 | + subgraph nb[Net Benefit] |
| 144 | + Dnb[0] |
| 145 | + Enb[0] |
| 146 | + Fnb["(1-pt) / pt"] |
| 147 | + Gnb["1"] |
| 148 | + Dall---Dnb |
| 149 | + Eall---Enb |
| 150 | + Fall---Fnb |
| 151 | + Gall---Gnb |
| 152 | + end |
| 153 | + end |
| 154 | +
|
| 155 | +
|
| 156 | +
|
| 157 | + style A fill:#E8F4FF, stroke:black,color:black |
| 158 | + style B fill:#E8F4FF, stroke:black,color:black |
| 159 | + style C fill:#E8F4FF, stroke:black,color:black |
| 160 | + style D fill:#C0FFC0,stroke:black,color:black |
| 161 | + style Dall fill:#C0FFC0,stroke:black,color:black |
| 162 | + style Dnb fill:#E8F4FF,stroke:black,color:black |
| 163 | + style E fill:#FFCCE0,stroke:black,color:black |
| 164 | + style Eall fill:#FFCCE0,stroke:black,color:black |
| 165 | + style Enb fill:#E8F4FF,stroke:black,color:black |
| 166 | + style F fill:#FFCCE0,stroke:black,color:black |
| 167 | + style Fall fill:#C0FFC0,stroke:black,color:black |
| 168 | + style Fnb fill:#FFCCE0,stroke:black,color:black |
| 169 | + style G fill:#C0FFC0,stroke:black,color:black |
| 170 | + style Gall fill:#FFCCE0,stroke:black,color:black |
| 171 | + style Gnb fill:#C0FFC0,stroke:black,color:black |
| 172 | + style nb fill: #E8F4FF,stroke:black,color:black |
| 173 | + style pred fill: #E8F4FF,stroke:black,color:black |
| 174 | + style baselinestrategy fill: #E8F4FF,stroke:black,color:black |
| 175 | +
|
| 176 | + classDef subgraphStyle fill:#FAF6EC,stroke:#333,stroke-width:1px |
| 177 | + class trt,ut subgraphStyle |
| 178 | +
|
| 179 | +``` |
| 180 | + |
| 181 | +*Regardless* of ranking each prediction is categorised to a bin: 0.32 -\> `[0.3, 0.4)`. |
| 182 | + |
| 183 | +1. Categorise Absolute Risk: 0.32 -\> `[0.3, 0.4)` |
| 184 | + |
| 185 | +References: Pauker SG, Kassirer JP. Therapeutic decision making: a cost-benefit analysis. N Engl J Med. 1975;293(5):229-234. doi:10.1056/NEJM197507312930505 |
| 186 | + |
| 187 | +::: |
| 188 | + |
| 189 | +## PPCR |
| 190 | + |
| 191 | + |
| 192 | + |
| 193 | +```{mermaid} |
| 194 | +
|
| 195 | +graph LR |
| 196 | + subgraph trt[Treatment Allocation Decision] |
| 197 | + linkStyle default stroke:#000 |
| 198 | + A("😷<br>😷<br>😷<br>😷<br>😷<br>😷<br>😷<br>😷<br>😷<br>😷") -->|"Treatment 💊💊💊💊"|B("<B>Σ Predicted<br>Positives</B><br>💊💊💊💊<br>😷😷😷😷") |
| 199 | + A -->|"No Treatment"|C("<B>Σ Predicted<br>Negatives</B><br>😷😷😷😷😷😷") |
| 200 | + end |
| 201 | +
|
| 202 | + subgraph ut[Utility of the Decision] |
| 203 | + B -->|"Disease 🤢🤢🤢"| D["<B>Σ TP</B><br>💊💊💊<br>🤢🤢🤢"] |
| 204 | + B -->|"No Disease 🤨"| E["<B>Σ FP</B><br>💊<br>🤨"] |
| 205 | + C -->|"Disease 🤢"| F["<B>Σ FN</B><br>🤢"] |
| 206 | + C -->|"No Disease 🤨🤨🤨🤨🤨"| G["<B>Σ TN</B><br>🤨🤨🤨🤨🤨"] |
| 207 | + end |
| 208 | +
|
| 209 | +
|
| 210 | +
|
| 211 | + style A fill:#E8F4FF, stroke:black,color:black |
| 212 | + style B fill:#E8F4FF, stroke:black,color:black |
| 213 | + style C fill:#E8F4FF, stroke:black,color:black |
| 214 | + style D fill:#C0FFC0,stroke:black,color:black |
| 215 | + style E fill:#FFCCE0,stroke:black,color:black |
| 216 | + style F fill:#FFCCE0,stroke:black,color:black |
| 217 | + style G fill:#C0FFC0,stroke:black,color:black |
| 218 | +
|
| 219 | + classDef subgraphStyle fill:#FAF6EC,stroke:#333,stroke-width:1px |
| 220 | + class trt,ut subgraphStyle |
| 221 | +
|
| 222 | +``` |
| 223 | + |
| 224 | +By choosing PPCR as a cutoff the implied assumption is that you are concerned with resource constraint and assume no individual treatment harm. |
| 225 | + |
| 226 | +*Regarding* the ranking each prediction is categorised to a bin: if the absolute probability 0.32 is the 18th highest predictions out of 100, it will be categorised to the second decile -\> `0.18`. |
| 227 | + |
| 228 | +1. Calculate Risk-Quantile from Absolute Risk: 0.32 -\> `0.18` |
| 229 | + |
| 230 | +References: https://en.wikipedia.org/wiki/Precision_and_recall |
| 231 | + |
| 232 | +::: |
| 233 | + |
| 234 | +# ✍️ Declare Fixed Time Horizons 🌅 (📅🤬) |
| 235 | + |
| 236 | +The `fixed_time_horizons` argument is designed for the user to choose the set of time horizons to follow. |
| 237 | + |
| 238 | +Different followups contain different distributions of observed outcomes: Declare fixed time horizons for the prediction model, such as \[5, 10\] years of prediction for CVD evet. |
| 239 | + |
| 240 | +## 🪛 Update Administrative Censorng |
| 241 | + |
| 242 | +For cases with observed time-to-event is shorter than the prediction time horizon, the outcomes might change: |
| 243 | + |
| 244 | +- `Real Positives` 🤢 should be considered as `Real Negatives` 🤨, the outcome of interest did not happen yet. |
| 245 | + |
| 246 | +- Always included and Encoded as 0. |
| 247 | + |
| 248 | +- `Real Neagtives` 🤨 should be considered as `Real Censored` 🤬, the event of interest could have happened in the gap between the observed time and the fixed time horizon. |
| 249 | + |
| 250 | +- If adjusted: encoded as 0. |
| 251 | + |
| 252 | +- If excluded: counted with crude estimate. |
| 253 | + |
| 254 | +```{python} |
| 255 | +
|
| 256 | +import numpy as np |
| 257 | +
|
| 258 | +times = np.array([24.1, 9.7, 49.9, 18.6, 34.8, 14.2, 39.2, 46.0, 31.5, 4.3]) |
| 259 | +reals = np.array([1, 1, 1, 1, 0, 2, 1, 2, 0, 1]) |
| 260 | +time_horizons = [10, 20, 30, 40, 50] |
| 261 | +
|
| 262 | +# Icons |
| 263 | +def get_icon(outcome, t, h): |
| 264 | + if outcome == 0: |
| 265 | + return "🤬" if t < h else "🤨" |
| 266 | + elif outcome == 1: |
| 267 | + return "🤢" |
| 268 | + elif outcome == 2: |
| 269 | + return "💀" |
| 270 | +
|
| 271 | +# Displayed time |
| 272 | +def get_time(outcome, t, h): |
| 273 | + if outcome == 0: |
| 274 | + return t if t < h else h |
| 275 | + else: |
| 276 | + return t |
| 277 | +
|
| 278 | +# Final output |
| 279 | +final_data = [] |
| 280 | +
|
| 281 | +for i in range(len(times)): |
| 282 | + id_ = i + 1 |
| 283 | + t = times[i] |
| 284 | + r = reals[i] |
| 285 | +
|
| 286 | + for h in time_horizons: |
| 287 | + outcome = r if t <= h else 0 # override outcome after horizon |
| 288 | + final_data.append({ |
| 289 | + "id": id_, |
| 290 | + "time_horizon": h, |
| 291 | + "time": get_time(outcome, t, h), |
| 292 | + "real": get_icon(outcome, t, h) |
| 293 | + }) |
| 294 | +
|
| 295 | +ojs_define(data = final_data) |
| 296 | +
|
| 297 | +``` |
| 298 | + |
| 299 | +```{ojs} |
| 300 | +
|
| 301 | +filteredData = data.filter((d) => d.time_horizon == timeHorizon) |
| 302 | +
|
| 303 | +viewof timeHorizon = Inputs.range([10, 50], { |
| 304 | + step: 10, |
| 305 | + value: 50, |
| 306 | + label: "Time Horizon" |
| 307 | +}) |
| 308 | +
|
| 309 | +Plot.plot({ |
| 310 | + x: { |
| 311 | + domain: [0, 50] |
| 312 | + }, |
| 313 | + y: { |
| 314 | + domain: [0, 11], |
| 315 | + axis: false |
| 316 | + }, |
| 317 | + marks: [ |
| 318 | + Plot.ruleX([timeHorizon], { |
| 319 | + stroke: "#D9E8A3", |
| 320 | + strokeWidth: 6, |
| 321 | + strokeDasharray: "5,5", |
| 322 | + y1: 0, |
| 323 | + y2: 10 // Should match the y-domain max |
| 324 | + }), |
| 325 | + Plot.ruleY(filteredData, { |
| 326 | + x: "time", |
| 327 | + y: "id", |
| 328 | + strokeWidth: 1.5 |
| 329 | + }), |
| 330 | + Plot.text(filteredData, { |
| 331 | + x: "time", |
| 332 | + y: "id", |
| 333 | + text: "real", |
| 334 | + tip: true, |
| 335 | + fontSize: 30 |
| 336 | + }) |
| 337 | + ] |
| 338 | +}) |
| 339 | +
|
| 340 | +``` |
| 341 | + |
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