Abstract To estimate causal effects. analysts performing observational studies in health settings utilize several strategies to mitigate bias due to confounding by indication. There are two broad classes of approaches for these purposes: use of confounders and instrumental variables (IVs). Because such approaches are largely characterized by untestable assumptions. https://safeersappliancers.shop/product-category/liebherr-cuel2831-55cm-fridge-freezer-silver-265-litres-a/