The business benefits of employee engagement are well known and include lower accident rates, fewer sick days, increased profits and lower staff turnover (saving not just money but time and stress as well!). The MacLeod Report, commissioned by the UK Govt, quantified some of these benefits.
There is a clear link between good leadership and engagement. Here's a short article which elaborates on this fact with particular focus on the need to be respectful, communicate well and promote fairness and accountability: https://bit.ly/2OHMVu2