Continuous Improvement vs. Continual Improvement

Most organizations implementing lean principles today do not in fact practice “continuous improvement”. What they practice would be better termed “continual improvement”. The distinction between continual improvement and continuous improvement is a fine but important one. Continuous means “without interruption” while continual means “frequent, repeated or seemingly without interruption”. Continuous is “go go go…” while continual is “start stop start stop start…” Continual improvement is far better than no improvement at all but it is far from world class and not the aim of lean.
In practical terms you can think of an alarm clock ringing and ringing without interruption as continuously ringing. Hitting the snooze button of a ringing alarm clock only to have it start ringing again later that morning and then hitting the snooze button again, would be an example of a continually ringing alarm clock. If the alarm clock did not go off at all and we could sleep in that may be ideal, just as it may be good to take a break from kaizen on some days so that ideas and energies can be refreshed. Neither continuous improvement nor continual improvement implies that we spend every waking (no sleeping) moment doing kaizen.
For some reason many organizations implement lean from the middle of the organization outwards. One possible reason is that the sponsorship from lean is at middle or senior management rather than the very top of the organization. This creates the need to implement lean as a series of projects led by lean experts rather than a transformation led by a fully engaged leadership and management team. These projects may be very successful. Often they are designed to demonstrate how lean systems will deliver specific desired business results. But projects have scopes and boundaries and by definition are discrete or at best continual and not continuous activities.
Kaizen events break projects down into a more frequent and repetitive series of rapid improvement activities. I know many good companies who have “continuously” been running kaizen events month after month for over a decade. But I am skeptical that relying chiefly on kaizen events represents true continuous improvement. Combined with projects that look across an entire site or value stream, kaizen event-driven lean implementation can greatly accelerate change. The glue that holds these kaizen activities and events together and makes continuous improvement possible is the practice of kaizen as part of daily management.
Kaizen in daily management includes everything from managers finding teaching moments with their subordinates as they make their walks through the gemba, to team leaders helping team members develop complaints into problem statements into root cause analysis exercises and implemented suggestions, to the engineer or manager running to the red andon lamp and making a rapid response to problems that have been identified and escalated.
In other words continuous improvement is not about the exciting, high-energy kaizen events and high-impact lean implementation projects but all about the sometimes boring grind that gets us through the day. The good news is that there’s plenty of it for all of us. If that doesn’t get you up in the morning there’s always continual improvement for you.

6 Comments

  1. Gabriela

    June 9, 2008 - 8:44 am

    In our corporation, we call this continuous kaizen “Employee suggestion program” or “Lean suggestion program”. In my company it is known as the “Kaizen program”. As they see opportunities for improvement, our employees come with suggestions and they write them down on Kaizen idea submittal forms. The supervisor initials them. A lot of times, they have been implemented already and we only record them. We have a committee (cross functional team of volunteers) and, for the ones that haven’t been implemented yet, we decide on their feasibility. Sometimes they are easy to implement, sometimes it’s more expensive and involved but the cost is justified, and sometimes they are not realistic and we try to adapt the idea to something that makes more sense or ultimately, we reject it. There is still room for improvement as to how to free up personnel so we have a larger participation and how to involve more the idea initiators, as they are tied to the line schedule, but there is certainly continuous improvement in all we do and this “Turtle speed” is just as powerful as the big jumps of the kaizen events, because it involves everyone in the organization, at all levels.

  2. John Hunter

    June 9, 2008 - 2:52 pm

    Dr. Deming preferred the term continual improvement because that would include continuous and dis-continuous improvement (innovation, etc.). I favor that way of thinking of it. But I think the improvement process
    must be never ending
    must focus daily on how any process can be improved
    must focus on adopting improvement systemically (not just locally, by one person or team)
    must focus on discontinuous improvement which could include high energy kaizen events and dramatic innovation
    must include a study (PDSA) phase where the improvements are evaluated to determine whether they actually had the anticipate effect
    and must include improvement of the improvement process itself.
    To me, continual improvement encompasses both continuous and discontinuous improvement.

  3. Jon Miller

    June 13, 2008 - 9:53 am

    I agree with your points of what improvement should focus on. I was not aware of Dr. Deming’s thought on continual improvement and I can’t say I completely agree.
    But as long as it’s persistent improvement, the terminology doesn’t matter.

  4. Anonymous

    July 15, 2009 - 2:25 pm

    Just because an improvement program is never ending, it isn’t continuous. The simple fact is, there is no such thing as “continuous” improvement, and I wish the proper word “continual” was used. Even your own so-called examples of “continuous improvement,” are in fact, continual.

  5. nick dalton

    December 28, 2009 - 11:21 pm

    continuous, continual? I agree with Miller (13/06/2008). Successful innovative products or processes are a result of persistent and iterative methodology

  6. SV Kishore

    October 24, 2010 - 8:05 pm

    My explanation of continual improvement is a consistancy of an improved parameter implemented at a given date to a predecided period and further improve the same parameter after proper analysis of results of consistancy .
    In continuous improvement the graph is steeply raising without a periodical analysis and lack of study of the effect of improvement on other elements of QM system like objectives , policy , customer complaints , quality etc etc.