Since 1989, the External Relations Office (ERO) of the Italian National Health Institute (NHI) has been a WHO Reference Centre for active learning. Since 2004, the ERO has been providing distance training in Public Health for professionals, experimenting, innovative learning methods based on the integration of active learning methodologies such as Problem Based Learning (PBL), which were originally devised for classroom learning, with e-learning tools. PBL is a methodology that challenges participants to "learn to learn" by working in small groups to solve real-world problems that mirror their working context, with the goal of developing life-long learning skills. This way, the process of working towards the understanding or solving of a problem leads to the participants' learning. The aim of ERO's work group as to e-learning development consists of finding innovative models to reproduce PBL in the e-learning context through the best available web tools. Moodle was chosen in 2005.

Following a first experience with a commercial platform in 2004, which was not adequate to support either the high number of participants, nor ERO's teaching methodology, a series of accurate evaluations began, in order to select a new platform able to respond to such needs. Moreover, there was the necessity to choose an open source platform, compliant with W3C guidelines and with Italian law on accessibility. Usability, stability, and security were crucial features, too. At the time of the evaluations, Moodle was suitable for becoming accessible and its availability of tools met ERO's methodology needs. Thanks to the NHI's will and financial support and with the Italian Moodle partner's active support, an accessible version was released in 2007 for the entire Moodle Community. At the same time, ERO's work group was strongly involved in the development of an e-learning model that increasingly adhered to PBL. After providing training for five years andby using experimenting progressive interaction pattern both, among and between participants and the facilitator of the learning process (as defined by PBL methodology), in 2009, a six month training course on Continuity of Care had been carried out, as the online phase of a Master's degree in Clinical Governance for Internal Medicine. Actually, this training experience has represented, so far, the highest level of ERO's learning model.

In comparison with other e-learning courses previously provided, this project was characterized by high-interaction among participants, facilitation in small groups, virtual classroom activities, and required various web features for its implementation. Ultimately, all the essential requirements to start the experimentation, such as platform usability, flexibility, tools availability, and the possibility to develop a module for integrating an appropriate virtual classroom system, were included in Moodle. The entire PBL cycle has been set up using Moodle 1.9 tools such as forum, database, workshop, feedback, consultation (see the following table for a comparison between traditional PBL steps and the corresponding activities in platform). Moreover, the Moodle grouping function allowed the ERO's work group to assign a facilitator to each group (as suggested in PBL). Finally, the constructivist approach characterizing Moodle matched with ERO's active learning methodology.

The training path was successfully completed, thanks to the innovative method of providing the course based on a high level of interactivity and to the low number of participants (n = 33), who were divided into small groups (5-7), with the active presence of a facilitator. Pre and post-test, composed by using the quiz tool, showed a significant knowledge improvement (22 percent). The final Customer Satisfaction Questionnaire, composed by using the feedback tool, showed a high level of satisfaction among participants, mainly as to the innovative learning method and the platform usability.

This experience represents an important basis for future improvements and experimentations. Thanks to the distance learning, this crucial phase of the Master's degree reached participants coming from all the regions of Italy. The participants, all specialists in internal medicine, despite the strict timetable planned and their job commitment, were able to carry on the activities during after-work hours, all day long. The participants referred to an improvement in their computer based skills and in the ability of working collaboratively in groups. On the basis of such results, the institutions involved in the Master's degree decided to replicate the training course and asked ERO's work group to collaborate in implementing further learning experiences.

This experience showed that high interaction leads to high levels of satisfaction among participants.

Actually, although large numbers of participants could be reached through e-learning, high interaction is possible only for courses with limited number of participants, as each small group requires the presence of a facilitator. Meetings in a virtual classroom, crucial for a good interaction during the key phases of PBL, require small groups as well. Furthermore, thanks to its flexibility, Moodle can be used for purposes other than learning, such as communication system, project activities, and documents sharing. Indeed, ERO is currently using Moodle for the communication between experts and staff developing curriculum for a medical college in Liberia, in the framework of another project that the ERO's staff is implementing.

It should be considered that the implementation of a learning project requires considerable planning. In order to create an accessible learning project, particular attention should be paid to documents accessibility. High involvement of an adequate staff endowed with different skills (technology, planning, communication, web writing, and training methodology) is also necessary. Furthermore, it must be considered that a high interaction among participants necessarly requires a low number of enrollements. Infact, the higher the chosen level of interaction is, the lower the number of participants needs to be.

Moodle 2.0 version will allow the ERO's workgroup to improve the preceding model with new tools and features. Indeed, the availability of conditional activities could be an important tool in order to schedule activities according to certain conditions, such as previous activity completion, as set in the course timetable. Moreover, blended learning should be considered as a possible way to facilitate interaction among participants and to robustly reproduce the PBL cycle on the platform.