Hello, for today module I'll be focusing on estimating activity duration. Since this class is focused on product initiation and planning, and not focusing on construction cost estimation, I'm gonna highlight main components that a planner has to think about in his team whenever there is an estimator, of course, with him on what items I want to look at, the basics, the foundations when I deal with estimating any kind of construction activity or task duration. I would love to highlight here five points that activity duration that largely determines volume, and we'll go one by one with some examples. The first one, the nature of the work that the activity entails. What we mean by that Is if all factors are equal, to pour a concrete in that 20th or 18th or 17th floor in my building will take longer than pouring the concrete to the third floor. So this is what we mean by the nature of the work. Second, the quantity of the work. An example, activity with let's say 8,000 square meter or square feet of form work to be placed in my project will take longer than a 4,000 square feet. In matter of fact, all things the same and all factors equal, it will take double the time of placing the 4,000 square feet or square meter of form work. So this is what we talk about, the quantity, third the technique or the construction methodology that is used in that activity. So let's take an example, concrete pouring will take longer with using a crane and buggies than using a concrete bump. So the construction technique needs to be addressed when look at estimating that activity, and of course you want to look at the cost, you want to look at what's available for you from a time perspective, and so on. On what construction technique that you want to use in that activity or task. Number four is the resources used to perform the work. For example, 20 masons are most likely, will finish the same amount of work that 15 masons or 12 masons do. So this is one, another example of the resources used would be a larger fleet of scrapers will finish and if moving operation faster than smaller one or smaller team. The last one I want to highlight is the working hours for the resources. For example, an activity or construction task will be finished earlier if accused ten hours shift per day, instead of just, eight hour shift per day. So, one main approach or method to estimate an activity duration is actually to look at the historical records of that particular construction activity or task and come up with, kind of the average duration from past experiences, and then make the final estimate. Moreover, you want to put into consideration that since the scope of the construction activity is unlikely to be identical between different projects, especially in our industry. In this case, unit productivity rates are typically used to overcome this kind of a challenge and we will go through an example in the following slide. In sum up,the activity duration is often estimated based on the experience and the judgment and the quantity of work, or the crew daily output from historical records. And here, in North America, we use the oddest means a lot In such tasks. And all this means it's actually that North America's leading supplier of construction cost information that will help us in the estimations also on the duration. So all this means, give us information such as the daily output for a specific crew, for a specific construction activity or task. And once we have this daily output, and knowing what's the quantity for to be performed, in that specific task, then the activity duration per days would be able to figure it out. So let's take an example here. Let's estimate a construction activity duration of 6,000 square feet, in the US, we're using a lot of square feet of course, but you can for simplicity have a square meter if you're using square meter in your projects. So you want to estimate that activity for a form work of continuous wall footing, so let's assume we have two crews that working in that specific construction activity or task and we can use, it says each plywood section up to three times. So, the way we would look at it or how to solve this, as I explained to you in the previous slide, we have the equation of the activity duration, that's what we want to find, and we know the quantity of work which is the 6,000 square feet. So we go to the hardest means to find For a continuous wall footing, a place in the form work and using each plywood three times we find out that there is 470 square feet per day per one crew. For the three users of that plywood section. If I know the 470, output rate, and the one day of work I have is 6,000, and the daily output was 470. So we will divide the quantity over the output rate from the hardest means were found and we will get around 13 days because we have two crews not one crew and the 470 only for one crew. Then we divide the total duration by two crews to know exactly that we have seven days, approximately, to finish this construction activity. So this is our estimate. In practice, if you remember I told you to focus also in the experience and the judgment by a good planner and a good estimator. So in a practice, for sure, you would need to check your estimates by a superintendent or an experienced estimator that works with the planning team, instead of just depending on the mathematical analysis for the equations that we just showed here. Also, there's something to think about having the number seven here. Working days is different than calendar days. So, five working days equal one week in a calendar day, from Monday to Friday. Some countries have them maybe from Sunday until Thursday. So that's the things from a judgement and common sense to consider when you do these estimations for duration of any construction task or activity.