Complex sentence: Atkins & Wood, 2002 Employers outsourcing of human resources functions also has created a market for 360-degree feedback tools from consultants, which has led to a proliferation of these tools on the market.
Split into simpler sentences: Atkins & Wood, 2002 Outsourcing of human resources functions also has created a strong market for 360-degree feedback products from consultants. This has led to a proliferation of 360-degree feedback tools on the market.