The Critical Path
Mike Kallet
CEO, Managing Partner and Author - Headscratchers (Critical Thinking Training)
Project managers know Critical Path to be the longest sequence of activities, from project start to finish, that must be completed to ensure the project is finished by a certain time.?A related expression is the “long pole in the tent”, referring to the element of the project that if delayed will cause the project to be delayed.
Whether it’s a project at home or at work, most projects have multiple steps to complete. If you want to finish by a certain time, then you must figure out when to start.?Three important elements to understand the starting point, as well as some of the risk factors, are the Critical Path, Lead time, and the Order of Things.
In order to figure out when to start a project, so that you can finish by a certain time, you have to know the steps along the way.?You have to understand what order tasks need to be in, how long each will take, and what can be accomplished in parallel or in sequence.?
Here’s a simplified example. Let’s say are preparing a meal for visiting guests.?How much time should you leave for this?
Here are the to-do items.
1.?Plan the meal, recipes and make a grocery list – 1 hour
2.?Buy the food – 1.5 hours
3.?Prepare the food 1 hour
4.?Pre-heat oven 10 minutes
5.?Cook the food – 2.5 hours
6.?Set the table, pour the drinks 0.5 hours
#3 and #4 can be done in parallel, and since #3 takes more time, we don’t have to count #4 in the timeline.?Same for #5 and #6.?As the food is cooking, you can set he table, so we don’t have to count #6 in the timeline.?As a result,?the critical path becomes #1 plus #2 plus #3, plus #5, for total of 6 hours.?If you start at Noon, you’ll be able to eat at 6:00 PM.
BUT .. what if the grocery store doesn’t have all the ingredients you need??YIKES.??So you decide to go to the grocery store a day or two before your big day just in case.?We call this lead time.?It’s the time do you need to do things in advance, so that you can stay on your schedule.
Another example of lead time is making a doctors appointment for your annual physical. I don’t now about you, but my doctor gets booked up months in advance.?So while the visit only takes an hour, I need to plan on the event months in advance.??If I want an appointment in December, I have to call in September.??Part of the critical path becomes the lead time to actually make the appointment.
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Say you’re planning a vacation.?While it might only take a day or two to find a hotel or Airbnb, and only takes a short time to buy an airline ticket, things get booked up (or very expensive).?You need the lead time weeks or months in advance to make the reservations.?The critical path includes this lead time.
The order of things is also important.?If you are going to paint a room in your house, you must buy the paint first.?You must decide on the color before you buy the paint.??
The Takeaway:
In order to finish a project on a schedule, you need to figure out when to start.?To do this, you need to understand …
? All the steps, the things to do and how long each will take
? The order that things must be done
? What can be accomplished in parallel or must be done in sequence
? What lead time do you need for the steps
With this you can figure out the critical path, i.e. the least amount of time you need to get something done, and that will then tell you when you must start.
Mike Kallet; CEO Headscratchers
For information about our on-site and Virtual Critical Thinking Workshops, visit www.headscratchers.com
Mike Kallet, CEO and Principal - Headscratchers LLC Author of Think Smarter - Critical Thinking to Improve Problem-Solving and Decision-Making Skills.?
Visit Think Smarter https://www.headscratchers.com/ThinkSmarterBook.html