Ecolego can be applied in a variety of areas, but is mainly used for risk assessment in radioecology,[1] environmental physics and PBPK modeling.

The software was initially developed as a complementary user interface to create compartmental models in Simulink.

Simulink had very powerful and fast solvers for ordinary differential equations, but lacked support for running probabilistic simulations and handling of parameter values.

The user interface of Ecolego was completely remade, and now used a tiling window manager to improve model transparency.

The user interface was improved with many new windows for navigation, report generation and presentation of simulation results.

The initial idea of Ecolego was to facilitate creation of large and complex models and to be able to solve difficult numerical problems.

Combined with hierarchical containers (sub-systems), the interaction matrix greatly facilitates construction and documentation of large and complex models.

Ecolego can also create reports that contain everything from interaction matrices, to parameter values, equations, decay chains, plots and tables.

By adding modules to the integrated library, a user can create a palette of validated building blocks that can be combined to form new models.

With an extensive list of probability density functions, together with Monte Carlo and Latin hypercube sampling and parameter correlation settings, Ecolego holds all the required tools to perform advanced probabilistic analysis.