TL;DRData labeling is the human bottleneck — supervised ML is only as good as its labels.
Supervised models need labeled examples, and quality labeling is slow, costly, and error-prone. Strategies: clear guidelines, multiple labelers with agreement metrics, active learning (label the most informative examples first), and quality audits. "Garbage labels in, garbage model out." Often the highest-leverage improvement isn't a fancier model — it's better, cleaner, more consistent labels.
Key points
Supervised quality is bounded by label quality
Labeling is slow, costly, error-prone
Guidelines + agreement + active learning help
Better labels often beat a fancier model
Common mistakes
Vague guidelines → inconsistent labels
One labeler, no agreement checks
Investing in models before fixing labels
Try it: Explain why improving labels can beat upgrading the model.
Example code
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<body style="background:#06040d;color:#e6e0ff;font-family:monospace;padding:20px"><pre>noisy labels → ceiling on accuracy
clear guidelines + multiple labelers + audits
→ cleaner labels → better model than a bigger one</pre></body></html>