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A B A B 1 2 Activity level [%] Time [weeks] 1 2 Time [weeks]
1 2 Activity level [%] Time [weeks] ~1 day Time [weeks] Time [weeks] Multi-tasking efficiency is a myth When we run projects today, we let people work on several projects simultaneously – this we may call “Multi-tasking”. But is this really efficient? If we look at Fig 1. we have various ways to run the two projects we call A and B, both demanding 10 weeks full time work. It seems to be virtually irrelevant whether we run 1 week with A and then 1 week B, etc (multi-tasking) or if we first make A fully ready before we start with B (single-tasking) in both cases we are ready after 20 weeks… But - if we look at this closer and calculate the “Average time per project”, using multi-tasking we get 19.5 weeks per project because A is ready after 19 weeks and B after 20 weeks, i.e. average 19.5 weeks. If we run single-tasking, A is ready for launch after 10 weeks (see the red flags) while B is ready for launch after 20 weeks, both calculated from time = 0. The “Average time per project” is now only 15 weeks (as (10+20)/2 = 15). This means multi-tasking make the process slow down with 30% !! (as( )/15 =0.30) If we make a similar check with three projects (D, E & F) each demanding 6 weeks full-time work (Fig 2 ), we get the result that multi-tasking results in 41% longer average project time than the single-tasking way!! (Single-tasking = ( )/3 = 12 weeks. Multitasking =( )/3 = 17 weeks. Difference (17-12)/12 = 41%) In reality it is even worse. The reason is that we have shifting time between the projects. It takes time to re-programme yourself to what project B demands when you have done a whole week with project A. Let us say that after 1 day, you are fully re-programmed (Fig 3) and up and running at full speed and efficiency. This means 20% loss in time due to the shifting time if you have the interval of 5 days (1 week) for each project each time. Transferred to the situation first mentioned with the projects A and B, the full effect (Fig 4) is that you have 19 shifts in the multi-tasking way but only 1 shift in the single-tasking way. Including the shifting time this leads to the time loss for multi-tasking compared to single-tasking increasing from above mentioned 30% to 52% !! Transferred to a realistic situation (e.g. 4 projects à 26 weeks each, run in 0.5 week intervals but only ½ day time loss each shift) this means multi-tasking result in 66 % longer average project time!!! As an excuse speaking for multi-tasking you may state it is advantageous to have several projects to alternate with, because when there is a delay in one project due to “external circumstances” you can switch to another project instead. This may be true, but if you would run them the single-tasking way, you would not accept any delays. Instead you would turn every stone to fix these “external circumstances”, so I don’t buy that excuse. Single-tasking indeed means increased focus and dedication. You also have other delaying effects of multi-tasking, such as you can’t meet with the project team members when needed. You often have to delay meetings, because “your” team members are occupied in other project meetings or activities. (You do recognize yourself, don’t you??) Takeaway: The calculations above strongly indicate one, major message; Reduce the number of projects so people can practice single-tasking, i.e. 1 (one) project at a time!!! Finish old activities before starting new. Reduce lead times accordingly. Doing this we will deliver projects faster & better. 5 10 15 20 5 10 15 20 A B 1 2 Time [weeks] Activity level [%] A A B B A A B B A B A A B B A A B B A A B B A A B B A A B B A B A A B B A B A B Average time per project = (19 +20)/2 =19.5 weeks Average time per project = ( )/2 =23.4 weeks Fig 1. Running 2 projects each demanding 10 weeks full time work + 30 % + 52 % A A B B Average time per project = (10 +20)/2 =15 weeks Average time per project = ( )/2 =15.3 weeks D E F D E F D E F D E F D E F D E F + 41 % Average time per project = ( )/3 =17 weeks Fig 2. Running 3 projects each demanding 6 weeks full time work Reduce the number of projects so people can practice single-tasking, i.e. 1 (one) project at a time!!! Finish old activities before starting new. D E F Average time per project = ( )/3 =12 weeks Fig 3. Effect of shifting time on projects after 1 shift Fig 4. Full effect of shifting time on projects A and B
![A B A B 1 2 Activity level [%] Time [weeks] 1 2 Time [weeks]](http://slideplayer.com./slide/15221832/92/images/1/A+B+A+B+1+2+Activity+level+%5B%25%5D+Time+%5Bweeks%5D+1+2+Time+%5Bweeks%5D.jpg "1. 2. Activity level [%] Time [weeks] ~1 day. Time [weeks] Time [weeks] Multi-tasking efficiency is a myth. When we run projects today, we let people work on several projects simultaneously – this we may call Multi-tasking . But is this really efficient If we look at Fig 1. we have various ways to run the two projects we call A and B, both demanding 10 weeks full time work. It seems to be virtually irrelevant whether we run 1 week with A and then 1 week B, etc (multi-tasking) or if we first make A fully ready before we start with B (single-tasking) in both cases we are ready after 20 weeks… But - if we look at this closer and calculate the Average time per project , using multi-tasking we get 19.5 weeks per project because A is ready after 19 weeks and B after 20 weeks, i.e. average 19.5 weeks. If we run single-tasking, A is ready for launch after 10 weeks (see the red flags) while B is ready for launch after 20 weeks, both calculated from time = 0. The Average time per project is now only 15 weeks (as (10+20)/2 = 15). This means multi-tasking make the process slow down with 30% !! (as( )/15 =0.30) If we make a similar check with three projects (D, E & F) each demanding 6 weeks full-time work (Fig 2 ), we get the result that multi-tasking results in 41% longer average project time than the single-tasking way!! (Single-tasking = ( )/3 = 12 weeks. Multitasking =( )/3 = 17 weeks. Difference (17-12)/12 = 41%) In reality it is even worse. The reason is that we have shifting time between the projects. It takes time to re-programme yourself to what project B demands when you have done a whole week with project A. Let us say that after 1 day, you are fully re-programmed (Fig 3) and up and running at full speed and efficiency. This means 20% loss in time due to the shifting time if you have the interval of 5 days (1 week) for each project each time. Transferred to the situation first mentioned with the projects A and B, the full effect (Fig 4) is that you have 19 shifts in the multi-tasking way but only 1 shift in the single-tasking way. Including the shifting time this leads to the time loss for multi-tasking compared to single-tasking increasing from above mentioned 30% to 52% !! Transferred to a realistic situation (e.g. 4 projects à 26 weeks each, run in 0.5 week intervals but only ½ day time loss each shift) this means multi-tasking result in 66 % longer average project time!!! As an excuse speaking for multi-tasking you may state it is advantageous to have several projects to alternate with, because when there is a delay in one project due to external circumstances you can switch to another project instead. This may be true, but if you would run them the single-tasking way, you would not accept any delays. Instead you would turn every stone to fix these external circumstances , so I don’t buy that excuse. Single-tasking indeed means increased focus and dedication. You also have other delaying effects of multi-tasking, such as you can’t meet with the project team members when needed. You often have to delay meetings, because your team members are occupied in other project meetings or activities. (You do recognize yourself, don’t you ) Takeaway: The calculations above strongly indicate one, major message; Reduce the number of projects so people can practice single-tasking, i.e. 1 (one) project at a time!!! Finish old activities before starting new. Reduce lead times accordingly. Doing this we will deliver projects faster & better A. B Time [weeks] Activity level [%] A. A. B. B. A. A. B. B. A. B. A. A. B. B. A. A. B. B. A. A. B. B. A. A. B. B. A. A. B. B. A. B. A. A. B. B. A. B. A. B. Average time per project = (19 +20)/2 =19.5 weeks. Average time per project = ( )/2 =23.4 weeks. Fig 1. Running 2 projects each demanding 10 weeks full time work % + 52 % A. A. B. B. Average time per project = (10 +20)/2 =15 weeks. Average time per project = ( )/2 =15.3 weeks. D. E. F. D. E. F. D. E. F. D. E. F. D. E. F. D. E. F % Average time per project = ( )/3 =17 weeks. Fig 2. Running 3 projects each demanding 6 weeks full time work. Reduce the number of projects so people can practice single-tasking, i.e. 1 (one) project at a time!!! Finish old activities before starting new. D. E. F. Average time per project = ( )/3 =12 weeks. Fig 3. Effect of shifting time on projects after 1 shift. Fig 4. Full effect of shifting time on projects A and B.")
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