What is Top Down Decision Making? 

Top down decision making is when the higher authorities in an organization make decisions unilaterally without the input of lower-level individuals who will be affected by or involved in the effects of the decision. This type of decision making is common in traditional, hierarchical organizations. 
 

What is Bottom Up Decision Making?

The Bottom-up Approach is a democratic, involving, and consultative style of decision making in which employee participation is promoted at all levels the organization. This approach to leadership is associated with a flat organizational structure.