Upload README.md with huggingface_hub

README.md

@@ -1,14 +1,21 @@
-# pockethb-base
+# pockethb-base (EXPERIMENTAL — not a measurement tool)
 
 base hemoglobin regressor from [pocketHb](https://github.com/jayanthvee/pocketHb). resnet18 finetuned on the [nature sci data 2024](https://www.nature.com/articles/s41597-024-03895-9) fingernail+hb dataset (n=250 subjects). subject-disjoint 70/15/15 split, seed 42.
 
-## test metrics (patient-level)
+## test metrics (patient-level, n=37 subjects)
 
 - MAE: 1.582 g/dL
-- RMSE: 2.235 g/dL
-- R²: +0.012
-- n = 37 subjects
+- RMSE: ~2.32 g/dL
+- **R² ≈ +0.01**
+
+**the R² being essentially zero is the headline finding.** this model is not meaningfully estimating hemoglobin. it has primarily learned to regress predictions toward the population mean (~12.55 g/dL). the MAE improvement over the dumb predict-the-mean baseline (1.77 g/dL) is marginal and mostly attributable to train/test mean drift, not learned image features.
+
+this is consistent with what every small-n open-source replication of the [Mannino et al. PNAS 2025 paper](https://doi.org/10.1073/pnas.2424677122) hits: the paper used 9,061 subjects with paired CBC labels (and 1.4M+ real-world uses). this dataset has 250 subjects with one photo each. there is not enough data here to recover the photo→Hb signal well at the population level.
+
+## intended use
+
+**only as an input to a per-user personalization layer.** the open-source contribution of [pocketHb](https://github.com/jayanthvee/pocketHb) is the personalization layer that calibrates this noisy base model to a users known baseline hemoglobin value (from a real CBC). without that calibration, this base regressor should not be used.
 
 ## not a medical device
 
-research replication only. not FDA cleared. do not use in place of a blood test.
+research replication only. **do not use to estimate anyones actual hemoglobin.** not FDA cleared, not validated clinically, not a doctor. if you need a hemoglobin reading, get a blood test.