Power evaluation in networks has been studied by many scientists. The problem has been usually considered from different areas as the problem of decision making by a group of agents, the problem of epidemic spreading, etc. Based on the intuition that a node becomes affected if its individual threshold is exceeded, we present a model how to measure the influence. The model considers chain reactions in a network and takes into account individual characteristics and the group influence of nodes as well as indirect interactions between them. Our main focus is to evaluate a pairwise influence between nodes and reveal the most powerful elements.