Building a simulation: the narrative event diagram

During the software specification for the SIMPLE learning environment it became clear that for many people involved there was a gap between the ability to conceptualise the scenarios making up a simulation and the capacity to reproduce those scenarios as a formal design. The narrative event diagram – or NED – was developed in response to this.

The aim of a NED is to provide a structure for taking the initial concept for a scenario, formalising it in a description and then enabling this description to be machine understandable in a format that is easy to interpret. NEDs use activities and ideas from structured systems analysis and wrap them in a more accessible format. The SIMPLE case studies examples of situations when the NED has been used.

The process of creating a NED is useful at two levels:

1. The end result is a diagram that can be applied using cheap, easy to modify materials (pencil and paper), with concepts and structure that can be transferred between human beings in a relatively efficient manner.
2. In a software implementation such as SIMPLE these benefits can be operationalised in the production of code or resources.

The core concept of the NED is based on the notion of activities taking place involving different entities (both Player Characters and Non Player Characters) generating a message (some information) which is then passed on to another entity (again either Player Characters or Non Player Characters). Activities are placed on a line representing the scope of the entity – for example, tasks that students perform are placed on the Player Character line.

A NED consists of four horizontal lines each representing a different scope for activity:

1. Critical events – major scenario exposition points such as background events preceding the start of a Player’s involvement in the scenario.
2. Player activities – any task that the Player (a single individual or a multiple individuals)
3. Non Player Character activities – any task or event that is performed by any entity in the scenario who is not the Player.
4. Staff activities – any task that is performed in administrative or managerial capacity by an overseer.

Last Modified: 4 June 2010