While speculators are focusing on price changes of the metal of their choice to set up a trade, the long term investor is better off studying the price changes over the long haul and the relative price changes of one precious metal to another. It is most common to compare gold to any other precious metal through e.g. a Gold-to-Silver, or Gold-to-Platinum ratio. This tells you how many ounces of the second precious metal one ounce of gold would buy.
Read the complete study at: Metals not equally precious investments ...
Thanks for the interesting link, looks like palladium is leading the other metals.