You always need to eat, but you don't always need to buy a new computer. The Health sector has historically been a very strong area. Like groceries, consumers that need medical attention tend to get medical attention regardless of the economic outlook. Drug companies and medical facilities are the types of firms you will find here. Medical advances and an aging population suggest that this sector will continue to be strong in the future.
Services covers a broad spectrum of companies.
This group includes companies such as lawn-care firms or temporary staffing concerns. Once again, this sector often does well when the economy is strong and people are willing to spend extra money on things they could do themselves. Technology is by far the most talked about sector. It also tends to be the most volatile sector. Technology firms tend to do well when the economy is strong.