Safety-I | Safety-II | |
Features of the approach | Analytic approach | Synthetic approach |
Definition of safety | The number of failures is small enough to be demanded | The number of successes is as high as possible |
Purpose and type of safety management | · Prevent things from going wrong | · Make things work well under fluctuations and constraints |
· Reactive safety management | · Advanced safety management | |
Target of learning | Learn from failure cases | Learn from daily practice |
How to understand the system to handle | · Static system without change (static system) | · Dynamic system that keeps changing from moment to moment (dynamic system) |
· Easy-to-use system (tractable system) | · Cumbersome system (intractable system) | |
How to perceive failure and success | The path of failure and success is different | Failure and success happen in the same way |
Relationship between process and result | Linear model (causal relationship) | Non-linear model (interaction and feedback) |
Human position in safety | Humans work negatively for safety and are a risk factor | Humans are essential to the safety and flexibility of the system |
How to perceive performance fluctuations | Harmful and should be removed as much as possible | Irreversible, useful, monitored and managed |
Points of interest | · What (event) happened | · What (phenomenon) is occurring in the behavior of the entire system |
· Why it happened | · How it happens (interaction) |