System dynamics: A soft and hard approach to modelling

System Dynamics (SD) can be employed for qualitative and quantitative modelling. There are important tools and methods within SD that can be easily accommodated within qualitative modeling, also known as Soft Operational Research or problem structuring method. While traditional stocks and flows are the basic components of quantitative SD modeling, quantitative SD modeling shares many commonalities, e.g. empirically driven, thorough testing, and critical focused to outputs, with traditional simulation methods and quantitative Operations Research tools. This tutorial informs novice modelers on the aspects to consider when they want to use SD as a qualitative and quantitative modeling method. In any approach employed, the use of SD modeling needs to be grounded in relevant literature from the perspective employed, qualitative or quantitative.