市场广度衡量的是"到底有多少只币/股在涨、多少在跌"，而不只是看一个综合指数的涨跌。Market breadth measures how many individual assets are rising versus falling, rather than just looking at whether an overall index is up or down.
一个指数可能因为少数几只大权重资产拉涨而显得"健康"，但如果大多数成分资产其实在下跌，这种上涨的根基就很窄。广度指标帮你看清涨势或跌势究竟是"大家一起动"还是"少数几个带头"。An index can look strong simply because a handful of large-cap assets are pulling it up, even while most other assets are quietly declining. Breadth indicators reveal whether a move is broadly shared across the market or driven by just a few outliers — giving you a fuller picture of what is actually happening underneath the surface.