Calculate the year-to-year gold-price return between two comparable annual observations and see the gain or loss on an optional gold holding.
This is a one-period price return. It is not a CAGR unless the period spans a continuous multi-year interval and is annualized appropriately.
Using year-end prices answers a different question from using annual average prices or a particular purchase date. State the endpoint convention when comparing historical yearly returns.
An investor's actual yearly return can differ from the quoted price return due to buying and selling spreads, physical premiums, storage costs, taxes and other transaction effects.
You can calculate its percentage change mathematically, but the result would represent the ETF price rather than spot gold.
Yes.
For exactly one comparable year, the concepts align; longer periods require annualization.