| Newsgroups |
gmane.comp.programming.software-in-process |
| Message-ID |
<[email protected]> |
This discussion of cycle time caused a raging debate in our family,
with Tom insisting that cycle time was takt time, and me insisting
it was the length of time from which an item enters a queue until it
gets through the queue. No, Tom said, that is lead time. No, I
insisted, lead time is the length of time it takes for an item you
ordered into inventory to arrive, and no one should be giving lead
time a different meaning.
The mystery was cleared up when I pulled out the operations
management text book I taught from a couple of years ago (Krajewski
& Ritzman, 5th edition). Here they had a long discussion of cycle
time which was clearly the same as takt time, and then in a footnote
they said:
"Except in the context of line balancing, *cycle time* has a
different meaning. It is the elapsed time between starting and
completing a job. Some researchers and practitioners prefer to use
the term *lead time*."
SO! Cycle time has TWO commonly used meanings one takt time and
one equivalent to time-in-queue.
There is no way I am going to use the term *lead time* to refer to
what I have fondly known as cycle time for years. To me, lead time
is the time it takes for an item to arrive in inventory once you
have ordered it from a vendor. This is still the common use of
lead time in construction so I will not confuse things by giving
lead time two meanings. Not after *cycle time* has been rendered
useless by someone corrupting it with two meanings.
I have decided to use the term *service time* to refer to the time-
in-queue definition of cycle time and takt time to refer to the line-
balancing use of the term cycle time.
At least it resolved our argument.
Mary Poppendieck
------------------------ Yahoo! Groups Sponsor ---------------------~-->
Get 128 Bit SSL Encryption!
http://us.click.yahoo.com/LIgTpC/vN2EAA/xGHJAA/NhFolB/TM
---------------------------------------------------------------------~->
To unsubscribe from this group, send an email to:
[email protected]
Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/