With today's educators subject to so many daily demands, it's easy for them to lose focus. Often their days are spent accomplishing tasks that require time and effort but have little or no impact on their success or the success of their students. When educators are forced to take this "doing everything correctly but nothing effectively" approach, student achievement suffers.
Doing everything correctly but nothing effectively also compromises the results of professional learning. Organizing professional development that increases the learning of educators and their students requires thoughtful data gathering and analysis, realistic planning, rigorous implementation, conscientious follow-up, and serious evaluation. Given the competing demands being placed on educators, it's no wonder that expedient, event-centered professional development is such a temptation. Scheduling a session and securing a speaker, consultant, or video is much easier than organizing deep learning experiences that are appropriate and useful. (from Education Week)
The above comes from an article which addresses key questions that districts and schools should consider as they plan and evaluate professional development.