sentences:  It is important to remember that while useful, surveys and indicators have limitations, and are at times subjective and incomplete.For example, no complete list of factors affecting quality of life can be created, and the way people weight these factors differs.The Office for National Statistics does not produce GVA data for the City of Manchester alone, instead the sub-region of Greater Manchester (GM) is divided into two groups of authorities to form NUTS 3 areas for statistical purposes