Even though management and organization development have been studied in vast amounts, a specific research – in which the results can be generalized to benefit the organizations’ development in practice – is lacking. Many studies indicate that certain human resource practices have improved the organization performance, but do not have the explanatory power. This dissertation presents effective organization development process based on tacit signal method that utilizes the employee tacit knowledge. Tacit signals are used in systematic organization development for implementing optimal improvement actions in the workplace level. These optimal workplace innovations are collectively agreed to be the development actions with the best value for improving the working society’s competencies and performance. In this research, the human tacit signal development process is evaluated in practical case studies. These case studies show that effective organization human competencies development correlates with both, human productivity as well as the capacity increase. These findings are explained with theoretically consistent calculations, hence increasing the research’s reliability and practical value.