Almost every company will backslide from the results of their Lean gains. I often describe kaizen as three steps forward, two steps back. If you can make it just one step back (or best of all, none!), you'll be way ahead of the game.
The key is to anticipate the backslide and take early, aggressive, organized steps to prevent it from happening before it starts. This is the responsibility of the area manager whose process was improved, as well as the Kaizen Promotion Office (KPO) and senior management. Actions can include a “kaizen newspaper” at the end of each event that lists any follow up actions, the dates they will be completed, and the person responsible for the work. Team leaders and senior managers should take a weekly gemba walk to review the progress on each kaizen run by the KPO office. In addition, the Team/Value Stream leader should provide an update on the sustainability of the kaizen results as part of his/her weekly report out to the CEO and senior management.
Keep in mind that even if you transform your organization and have the full engagement of your CEO, you'll still face lower-level managerial resistance. There are ways to anticipate this potential area of backsliding as well.
The key principle here is to make gains visible, explicit, and tied to clear plans for continued kaizen. If you establish a value stream organization with team leaders and create a weekly report out structure to the CEO and his/her staff focused on the key value drivers for your business--at Wiremold, for example, they were 100% on time customer service; 50% reduction in defects each year; 20% productivity gain each year; 20x inventory turns; establishing visual control and 5S everywhere)--then you'll see who is performing and who is not pretty quickly.
Second, if your CEO spends a lot of time on the shop floor and provides updates to all employees at quarterly profit sharing meetings, then people will speak up if the message they are getting from their manager is the same as it was before the lean transformation. It will become clear who is not on board. Talk to your team members and give them a chance, but if they refuse to work with you, try to get someone in the job who supports the change.
Above all remember that you should never do a kaizen and just walk away. Once you've made and sustained gains, schedule the next kaizen for that area to get to the next level of gains. Secure the gains you've acheived, share that learning, and then do it all again. After all, the word “kaizen” means continuous improvement. You can’t achieve that without going back again and again to remove the waste from your processes and actively, creatively problem solve.