I have taken part in many professional development training workshops, ranging from curriculum development, observation and assessment, school based intervention and play therapy to 21st century teaching and learning, and most recently IT sessions to assist with navigating technology for teaching and preparation to implement a drug prevention program for young children.
While the term continuous professional development is bandied about, as indicated by Daniel most of these training sessions are one-off, or if there is a repeat session it is so spread out that information is forgotten. While some of the information received is implemented there is limited follow up and evaluation to determine what strategies are effective, and the onus is on the administrator to observe and advise staff.
So for in-service training to be effective training must be repeated, short sessions/courses which are target specific not random and ad hoc sessions. Implementation of new information/strategies/ideas must be followed up with observation and recommendations given. Finally, teachers must be given a voice to share their input since they are the ones on the frontlines.
One particular training that I was exposed to was the use of play therapy. This as the name suggests is a way of of giving voice to children for them to communicate and express their feelings, while interacting/playing with materials such as puppets, toy animals even sand. At the end of this short course, materials were given to participants (like animals and sand), as well as a text book with more information. While I found everything exceptional, at the end of the day there was no follow up to determine how successful implementation was.