Composite metrics are derived from multiple questions that are either designed to remove issues with cultural / sample bias, or to track customer experience of all facets of a company. They have one big advantage: the ability to track closely key customer experiences. However, they can be more complex to run.
This is used in a number of places in the world to provide a reliable way to measure satisfaction across multiple companies or organisations. In the UK it's called UKCSI and is managed by the Institute of Customer Service. It's key advantage is it enables benchmarking with competitors. However, the lack of frequency of surveys and inability to target questions precisely to your business makes it difficult to use alone.
Building your own set of questions to derive a composite metric provides a precise method of tracking customer experience across your organisation. However, it does require more thought than a single metric. The following pages will show you how to do it, but we'd recommend using experts to make sure you get this right.