The two terms are frequently used interchangeably and can often be interpreted to mean the same thing. However, there are some key differences between the two.
Continual improvement means that the approach is repeated and has pauses in between repetitions. A continual approach will have a phased system, whereby improvements will be made then there will be a break to measure and analyse the success, after this further improvements can be made.
Whereas a continuous improvement approach does not stop, it is an uninterrupted flow. A continuous approach is one that will constantly look to make improvements, it is a sustained process of development.
One of the most common approaches of continuous improvement is Lean. This approach aims to embed a culture of continuous improvement (Kaizen culture) which uses a set of tools and techniques to reduce waste and maximise customer value.