To analyze ETF, you must analyze its internal structure. For example, the rise or fall in stock-based ETFs for natural gas directly depends on what’s happening with natural gas. An index-based ETF behaves just like an index.
During analysis, it is important to remember which ETF you are analyzing. If a reversal, then in case of growth in the asset (or group of assets) included in the ETF, the ETF itself will fall, and vice versa.