By using metrics we make it a lower dimensional model, that can be managed at scale. However in real world, it often becomes a overfit one. In large scale execu

By using metrics we make it a lower dimensional model, that can be managed at scale. However in real world, it often becomes a overfit one. In large scale execution, people only care what metric measures. A talk vs metrics is just higher dimension vs lower one. The information within a talk is complex. Different people received vary information from the same talk. So it's hard to managed by scale. So a metrics system is just a trade-off for its scale.