value read, not a signal. it says which metal is cheap against the ratio's own history, not which one will move next.
method: monthly gold/silver ratio (COMEX front-month closes, yahoo GC=F ÷ SI=F) from Sep 2000; band = 25th to 75th percentile of all past months, line = median. above the median, silver is cheap relative to gold; below it, gold is. our own band, not Tom's fair-value line.