Van Gysel asked in a recent post at Chandoo.org for a way to calculate the costs of running a plantation. The twist is that the costs vary by year, and based on the age of the trees.
The following is a slightly simplified version of the solution I offered:
=SUM(IFERROR(LOOKUP(“Year”&MMULT(N($B$3:B$7>0),TRANSPOSE(COLUMN($B$3:B$7)^0)), $B$11:$I$11, $B12:$I12),0)*B$3:B$7) Ctrl+Shift+Enter
Today I am going to try and explain how the formula works.
As always at Formula Forensics, you can follow along with a sample file: Download Here
The Problem
In a plantation, the costs for planting and maintaining trees vary based on the age of the trees and by year. The table below shows the acres of trees planted per year and the yield and costs per year that vary based on the age of the trees.
Let us look at the calculations needed for each year.
Year 2013
- 300 acres of trees were planted in 2013. Calculations for 2013 are as follows. (Only Yield calculation is shown, but the process is similar for Nursery costs, Fertilizers, etc.)
- The trees do not yield any fruits in the first year. As such, Yield for year1=300*0=0
That was easy!
Year 2014
- 700 additional acres of trees will be planted in 2014. Calculations for 2014 are as follows. (Again, only Yield calculation is shown, but others are calculated similarly.)
- 300 acres of trees are 2 years old. 700 acres are 1 year old.
- The 300 acres from 2013 now yield fruit since it is year2. However, the new trees (700 acres) do not yield any fruits yet. So total yield for 2014=300*Year2Yield+700*Year1Yield=300*5+700*0
Year 2015
- 1000 additional acres are to be planted in 2015. Calculations for 2015 are as follows:
- 300 acres are from 2013 (3 years old); 700 acres are from 2014 (2 years old); 1000 acres are from 2015 (1 year old).
- Yield for 2015=300*Year3Yield + 700*Year2Yield + 1000*Year1Yield = 300*10 + 700*5 + 1000*0
Year 2016
- 1000 additional acres are to be planted in 2016. Calculations for 2016 are as follows:
- Yield for 2016=300*15+700*10+1000*5+1000*0
How do we simulate the above calculation in an Excel formula?
A Solution
Let us first look at how we performed the calculations above manually, using the 2016 Yield as an example.
- We took each acreage value in 2016, and determined its age by counting how many years it has been since that acreage was planted. You might have observed that the age can be counted by the number of times a value has been repeated up to that point. (In other words, if I planted 300 acres in 2013, I should see that same amount in 2014, 2015 and 2016.) As such, 300 acres is repeated 4 times. 700 acres is repeated 3 times. 1000 acres is repeated 2 times. And the latest planting of 1000 acres exists only once.
- Once we determine the age for a given acreage, we looked up the yield for that age in the second table
- We then multiplied the acreage with the corresponding yield value.
Calculation #1 can be expressed as follows:
- Age for acreage 1 (first planted in 2013)=count of B3:E3 where value is greater than zero. i.e. COUNTIF(B3:E3,”>0”)
- Age for acreage 2 (planted in 2014)=count of B4:E4 where value is greater than zero. i.e. COUNTIF(B4:E4,”>0”)
- Age for acreage 3 (planted in 2015)=count of B5:E5 where value is greater than zero. i.e. COUNTIF(B5:E5,”>0”)
- Age for acreage 4 (planted in 2016)=count of B6:E6 where value is greater than zero. i.e. COUNTIF(B6:E6,”>0”)
- Age for acreage 5 is zero since nothing has been planted for 2017 yet in 2016
The above approach would work if we were calculating the age one row at a time. However, that can become tedious really fast. We need to perform the calculation for the full range (B3:E7) together, but return the counts for each row individually.
Excel’s MMULT function comes to the rescue!
MMULT (which stands for Matrix Multiply) multiplies two matrices and returns a third matrix based on rules for matrix multiplication. I am planning to devote a whole article to explain the MMULT function. As such, for this article, we will summarize the utility of the function as “take a 2-dimensional array, add each column’s value for each row, and return a 1-column array”.
MMULT requires that its arguments be numeric.
So to obtain the counts for the year 2016, we can use the following:
MMULT(N($B$3:E$7>0),TRANSPOSE(COLUMN($B$3:E$7)^0))
As you can see from the picture below, MMULT’s results are the addition of each column for each row.
In the above formula, you may have noticed that the range uses absolute and relative referencing (signified by the $ sign or lack thereof). This is to ensure that the range grows or shrinks as needed. The upper left address is held constant ($B$3). However, the lower right address for the range has columns that vary but row that is fixed on row #7. This ensures that the formula would work if we copy to the left, right, etc. in the final results.
Now that we have the age for each acreage value, we can look up the corresponding yield value using (what else?) LOOKUP function.
But before we can use LOOKUP, we will need to convert the numeric values returned from MMULT into the strings Year1, Year2, etc. found in the Costs table. Of course, you know how to do that… concatenate the string “Year” to the result from MMULT
“Year”&MMULT(N($B$3:E$7>0),TRANSPOSE(COLUMN($B$3:E$7)^0))
For the 2016 example, we get {“Year4″;”Year3″;”Year2″;”Year1″;”Year0”}
We can now use LOOKUP as follows:
LOOKUP(“Year”&MMULT(N($B$3:E$7>0),TRANSPOSE(COLUMN($B$3:E$7)^0)), $B$11:$I$11, $B12:$I12)
You may recall that LOOKUP looks up a value in the array indicated by the second argument, and returns the corresponding value from the third array argument. In this case, instead of looking up a single value, we look up an array of values (supplied in the first argument) to the function.
The above formula translates to the following:
LOOKUP({“Year4″;”Year3″;”Year2″;”Year1″;”Year0”}, {“Year1″,”Year2″,”Year3″,”Year4″,”Year5″,”Year6″,”Year7″,”Year8”}, {0,5,10,15,20,25,30,35})
The result from LOOKUP is {15;10;5;0;#N/A}
(The last value is #N/A because there is no acreage value for 2017 yet (as of 2016 column). The concatenation resulted in Year0 which does not exist in the “Age of The Trees” range (B11:I11) above.)
By using IFERROR(LOOKUP(…),0) we get {15;10;5;0;0}
We can now multiply the above result with the acreage values for 2016 to get {4500;7000;5000;0;0}
Finally, we SUM the values to get 16500
Putting it all together, we get the following formula (shown for Production for year 2016)
=SUM(IFERROR(LOOKUP(“Year”&MMULT(N($B$3:E$7>0),TRANSPOSE(COLUMN($B$3:E$7)^0)), $B$11:$I$11, $B12:$I12),0)*E$3:E$7)
One of the benefits of the above formula is that you can copy the same formula to calculate values for additional years, as well as other plantation costs.
Download
You can download a copy of the above file and follow along: Download sample file.
Let me know (using the comments below) what you think of the above approach and solution, as well as any other approaches you have utilized to solve a similar problem. In the meantime, I wish you continued Excellence!
-Sajan.
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28 Responses to “Team To Do Lists – Project Tracking Tools using Excel [Part 2 of 6]”
[...] & tracking a project plan using Gantt Charts Team To Do Lists - Project Tracking Tools Part 3: Preparing a project time line [upcoming] Part 4: Time sheets and Resource management [...]
the templates are great (I bought the combo).
What I'm missing is a way to have the project gantt chart and reporting with the data per resource, in such a way that I can also show the occupation per resource on an extended gantt chart.
So with hours entered per person per project or sub-activity, to show a gantt chart of how many hours/days a person spent on which project (or plans to spend).
[...] from: Team To Do Lists - Project Tracking Tools using Excel [Part 2 of 6] 25 Jun 09 | [...]
Hi Chandoo,
Funny I have a post on the value of MS project lined up which I will post when the current monster project I'm working on finishes and I get some free time!
I'm not sure this would help with any of the projects I've worked on, closing down a to do list seems like more effort than it's worth, but it might be useful for some things. I guessing it doesn't, but does the time stamp not update when you recalculate the work book?
keep up the good work!
Ross
@Ross.. Thanks for sharing your ideas... I think to do lists are a great way to keep up with project activities and ensure accountability from individual team members, when they are implemented right.
"I guessing it doesn’t, but does the time stamp not update when you recalculate the work book?"
Your guess is right. When you change the calculation mode to "iterative", excel takes care of the nittygritties and retains older values in circular references in formulas.
[...] Project Management in Excel [New Series] - Gantt Charts | To Do Lists [...]
[...] & tracking a project plan using Gantt Charts Team To Do Lists - Project Tracking Tools Project Status Reporting - Create a Timeline to display milestones Part 4: Time sheets and Resource [...]
Hi Chandoo,
The template give me lot of convenience to monitor the thing to do. It simple. Thank You
[...] & tracking a project plan using Gantt Charts Team To Do Lists - Project Tracking Tools Project Status Reporting - Create a Timeline to display milestones Part 4: Time sheets and Resource [...]
[...] make sure you have read the first 4 parts of the series - Making gantt charts [project planning], team todo lists [project tracking], project time lines chart [reporting] and Timesheets and Resource Management using Excel. Also [...]
Chandoo,
I really do not see any befit to this function in Excel unless it was somehow tied into some other chart. That is say a scheduled activities % complete is based on the to-do list.
The only way this chart would be useful is if no one was assigned none dependent task that could be done by anyone. The cases were both of these conditions are true are so few and far between it really makes this chart worthless.
@Brian... Once you have a todo list up and running, it is easy to get metrics out of it. I didnt propose it as it might look a bit too micro-management-ish.
I am able to understand what you meant by "The only way this chart would be useful is if no one was assigned none dependent task that could be done by anyone. The cases were both of these conditions are true are so few and far between it really makes this chart worthless."
Can you explain?
"Chandoo"
What I mean is this. Lets say you have 10 task which are part of one activity/WBS that is in your schedule. One there are very few cases were many people would be assigned to complete this one scheduled activity with no direction being given who should what of the 10 task. It is poor management, and the task 90% of the time would not get done in a timely manner if say 4 people were responsible. Secondly, you are assuming all 10 task are independent of each other. You might need to do task 1 thru 3 before you can do task 4, and to do task 7 you might need to do 4 and 6. Thirdly, the time it would take to compile and then fill out the to-do-list even in limited applications is really not worth it.
I just see almost no applications why a team would need to inform others separate from the schedule that they have completed a task on a to-do list unless anyone of the 4 people could of completed that task.
My point is, there might be a few very limited applications for this type of list but this list would be worthless as a Project Management tool in every other case.
However, change this from a to-do-list to a document change log and it is perfect. Instead of to-do it is the documents name or summary of what changed in the document. The person is who edited the document, and the time stamp is when they checked it in. But I do not know why you would use excel when there is free software you can use commercially that is 10 times better that does document management.
I think using excel to do Project Management over a real Project Management application is a bad idea. Unless you are running a very small, simple project, the time and effort is a lot more to use excel compared to the cost of the Project Management software.
This comes back to my point, I love your site, however, just because you can do something in excel does not mean you should do it. To often the time it takes to use excel is wasted 10 times over from the cost of doing it in an application designed to for the specific application.
@Brian: The todo list mentioned here is meant to keep track of all the tasks for which detailed planning is not necessary but some sort of tracking is needed. These are not be confused with project activities (a la gantt chart).
I like your suggestion about using this as a document tracker. Pretty cool use.
Coming to your point about excel as a real project management tool, well, I have my views, but in a serious project environment, it would surely payoff to have a dedicated project management application.
[...] & tracking a project plan using Gantt Charts Team To Do Lists – Project Tracking Tools Project Status Reporting – Create a Timeline to display milestones Time sheets and Resource [...]
Chandoo,
Wonder how the timestamp column will maintain its previous data. Both Today() and Now() functions will update as and when the next timestamp happens.
[...] Preparing & tracking a project plan using Gantt Charts Part2: Team To Do Lists – Project Tracking Tools Part3: Project Status Reporting – Create a Timeline to display milestones Part4: Time sheets and [...]
I've combined this with the issue tracker since I like the automatic date stamp, but one thing I'm noticing is that I can't replicate the chart that goes along with the issue tracker because the cells that are referenced have the formula that inserts the time stamp instead of a the actual date value. All the dates of the last 30 days display 0 when they should have a value.
Is there a way around this?
I have edited the chart so that my team members can update the percentage completion of the assigned tasks. When the cell is updated, i would like the time stamp to update. How would I manipulate the formula to update whenever the drop-down list is changed?
[...] … ??? To Do List [...]
Excel is great however sometimes you need to get a better idea of what tasks each person on your team is working on at any given time. We've developed a web app that can do just that! Each person has a list of tasks, listed in the order they have to complete them.
HII,
I want to expand the database through excel where i am working on 11 cities as of now and i want to expand it upto 50 cities and hence forth the data related to it will also expand so i want to make it precise where i can get updates also that this work is required to be done at that particular day or date
Thanks for making all of this information available for free. I am currently using excel to track everything for the first time. I later plan to output our information here with a more visual presentation. Wish me luck!
Can some one point me out to some additional direction on the "Who Finished it?" column? Something more 'basic' for a newbie excel guy? lol I got everything else working on this tutorial but that column. I can't seem to recreate it and I know a lot of it is due to lack of knowledge with VB code. I'd like to recreate this column very much 🙁
Dear Chandoo,
Thanks for the team to do list, kindly let me know how to set the column who " finished it " from another work sheet
Hi Chandoo,
Unable to download it - can you please check the link and confirm.
Great inhisgt! That's the answer we've been looking for.
Hi Team,
I know u all are the best programmers in the world!!! that's I am here to rectify my issues. here is my question please ans me as soon as possible before 8-3-2017 its really urgent.
I have a project named the production tracker.
1) I require the user form which shows the names of the Associates which are linked to the different tracks. when the user is selected the particular track related details and dropdowns should appear.
2) I need to track the associate needs how much of the time to complete the particular task. with start stop and pause and resume timer.
3) It should display the daily count of the production and save the data to the another Excel file.
this production tracker should save all the data no matter how many people logs in into it.
Please help me for this it will be very appreciated.
you can directly email me on my mail ID: tusharkch694@gmail.com