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--- this_is_lean_-_resolving_the_efficiency_paradox_-_niklas_modig [2016/11/02 10:16] – [Review and Notes] hpsamios
+++ this_is_lean_-_resolving_the_efficiency_paradox_-_niklas_modig [2018/02/21 05:19] – [Review and Notes] hpsamios
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   * Cycle time is the average time between two flow units’ completing the process and refers to the pace at which flow units move through the process.
-The book then looks at the theory of constraints - the law of bottlenecks states that throughput time in a process is primarily affected by the stage of the process that has the longest cycle time
+The book then looks at the theory of constraints - the law of bottlenecks states that throughput time in a process is primarily affected by the stage of the process that has the longest cycle time.
 Processes with bottlenecks have two key characteristics: Immediately prior to a bottleneck, there is always a line, regardless of whether it is material, information, or people flowing through the process. It is often clear which stage in the process is the bottleneck, particularly when the flow units are material or people. It can be more difficult to see the line at the bottleneck when the flow unit is information, but the line is there. The stages of activity after the bottleneck must wait to be activated, which means they will not be fully utilized. Because the bottleneck is the stage of activity that has the slowest throughput, the stages after the bottleneck will work at a slower pace than they could have.
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 These negative effects result in three “sources of inefficiency.” The first of these sources is related to people’s ability to deal with long waiting times. Secondly the non-fulfillment of a need can create new types of needs, which in turn create new needs. In other words, there is a chain reaction. Thirdly waiting time closes important windows of opportunity. Fourthly you create inventory and inventory requires additional resources.
-To understand the first and second order effects, take your email example. Too many emails trigger stress. Email is [art of what we do, but an inbox with 200 unsorted emails can be somewhat overwhelming. Where do you start? The primary need is to answer important emails. However, the large number of emails creates a secondary need for a strategy to sort emails. One strategy could be to address the emails in date order, while another could be to start with the most important people first. Or perhaps you could look for “flagged” messages or discard those emails on which you have only been copied. Whatever method you use, sorting, structuring, and searching are activities that fulfill the secondary need, which is to handle the large amount of email. The primary need is to read, answer, and store email, but the large number of messages necessitates certain activities in order to gain some kind of overview. Apart from creating unnecessary work, handling a large number of emails at once can also be stressful.
+To understand the first and second order effects, take email inbox processing, for example. Too many emails trigger stress. Email is part of what we do, but an inbox with 200 unsorted emails can be somewhat overwhelming. Where do you start? The primary need is to answer important emails. However, the large number of emails creates a secondary need for a strategy to sort emails. One strategy could be to address the emails in date order, while another could be to start with the most important people first. Or perhaps you could look for “flagged” messages or discard those emails on which you have only been copied. Whatever method you use, sorting, structuring, and searching are activities that fulfill the secondary need, which is to handle the large amount of email. The primary need is to read, answer, and store email, but the large number of messages necessitates certain activities in order to gain some kind of overview. Apart from creating unnecessary work, handling a large number of emails at once can also be stressful.
 But there is more to it than that - another source of inefficiency: many restarts per flow unit. Starting over on the same task generates mental set-up time. Restarts are created when you have to start over on the same task. Continuing with the management of a large email inbox as the example. There is a high risk that you will need to read messages more than once. Some messages are simply too complex to deal with at that time, so you read them, file them, and return to them later. Sometimes you have to come back to them more than once, perhaps because you need further information. When work to be done just sits in a pile waiting, it is easy to lose sight of the big picture. The time and energy we spend on categorizing and structuring the work creates delays. The delays and the different type of activities (such as searching, identifying, categorizing, and structuring) mean that we have to re-familiarize ourselves repeatedly with the same information. The challenges of starting over on the same task are also driven by mental set-up times. A person needs time to focus his or her mind on a task, and it is mentally challenging to deal with several tasks at the same time. It is particularly challenging when we must repeatedly shift our focus from one task to another. The fewer tasks we have to deal with at the same time, the easier it is to focus. The more frequently we have to switch between tasks, the longer the mental set-up time becomes in relation to the total time. Therefore, the limitations of the human mind mean that a high number of restarts will generate new secondary needs that would not have been created if the work had been finalized the first time.