Deciphering a Number Formula

[Cole]

I just started a project and adopted a schedule with the below formula.
No one knows the intent of the formula which is in a Number Field...can
you guys help me decipher it?

Start is the 'Start Date'
Start 2 is the 'Status Date' (it's set every month)

I understand the first part says if the Status Date is more than one
month of the Start Date.

It's the part that follows I'm having a hard time deciphering.

Is the (1.946/7) and (1.82/7) a common formula in MS Project?

IIf((Start2-Start)>32,([Start2]-[Start])-((1.946/7)*(Start2-Start)),([Start2]-[Start])-((1.82/7)*(Start2-Start)))

Thanks for the help.

 

[JackD]

Closest thing I can guess is that someone doesn't know how to do date math
within project and is using those numbers to subtract weekends.
If that is the case simply rewrite the formula and use the projdatediff
function. The new formula would be:

ProjDateDiff([Start],[Start2],"standard")

The standard is an optional argument which names the calendar that should be
used for the math. This way it takes into account whatever holidays you have
entered as well.

For more information look here:
http://zo-d.com/blog/archives/progr...b-datediff-and-applicationdatedifference.html

Try it in a separate field and I think you will find the results are very
close to what the other formula gives. The formula I gave you is more
accurate though.

-Jack Dahlgren

 

[Cole]

Thanks Jack.

Weekends are not work days not sure if that makes a difference.. How
does the math part of the formula take out the weekends?

IIf((Start2-Start)>32,([Start2]-[Start])-((1.946/7)*(Start2-Start)),([Start2]-[Start])-((1.82/7)*(Start2-Start)))


Thanks for helping me understand.

Closest thing I can guess is that someone doesn't know how to do date math
within project and is using those numbers to subtract weekends.
If that is the case simply rewrite the formula and use the projdatediff
function. The new formula would be:

ProjDateDiff([Start],[Start2],"standard")

The standard is an optional argument which names the calendar that should be
used for the math. This way it takes into account whatever holidays you have
entered as well.

For more information look here:
http://zo-d.com/blog/archives/progr...b-datediff-and-applicationdatedifference.html

Try it in a separate field and I think you will find the results are very
close to what the other formula gives. The formula I gave you is more
accurate though.

-Jack Dahlgren

I just started a project and adopted a schedule with the below formula.
No one knows the intent of the formula which is in a Number Field...can
you guys help me decipher it?

Start is the 'Start Date'
Start 2 is the 'Status Date' (it's set every month)

I understand the first part says if the Status Date is more than one
month of the Start Date.

It's the part that follows I'm having a hard time deciphering.

Is the (1.946/7) and (1.82/7) a common formula in MS Project?

IIf((Start2-Start)>32,([Start2]-[Start])-((1.946/7)*(Start2-Start)),([Start2]-[Start])-((1.82/7)*(Start2-Start)))

Thanks for the help.

 

[JD]

Take a look at it.

The x/7 part surely refers to weeks and is subtracted from the complete
duration. In both cases x is almost 2 but is slightly less. I take this to
be some averaging on the part of whoever wrote the formula. I suspect that
in a month of 31 days there are an average of 31 - (1.82/7*31) working days.
When the duration gets longer then the average gets closer to duration -
(2/7 * duration). but doesn't quite reach there.

So in essence, the author of the formula took a basic formula of duration -
2 days for every 7 of duration and tweaked it to be more "accurate".
However, Project already offers a simpler, more accurate method of doing
this so I'd abandon this approach. What is that column titled? What is is
used for? That should give you the final clue you need to be 100% certain.

-Jack Dahlgren

Thanks Jack.

Weekends are not work days not sure if that makes a difference.. How
does the math part of the formula take out the weekends?

IIf((Start2-Start)>32,([Start2]-[Start])-((1.946/7)*(Start2-Start)),([Start2]-[Start])-((1.82/7)*(Start2-Start)))


Thanks for helping me understand.

Closest thing I can guess is that someone doesn't know how to do date
math
within project and is using those numbers to subtract weekends.
If that is the case simply rewrite the formula and use the projdatediff
function. The new formula would be:

ProjDateDiff([Start],[Start2],"standard")

The standard is an optional argument which names the calendar that should
be
used for the math. This way it takes into account whatever holidays you
have
entered as well.

For more information look here:
http://zo-d.com/blog/archives/progr...b-datediff-and-applicationdatedifference.html

Try it in a separate field and I think you will find the results are very
close to what the other formula gives. The formula I gave you is more
accurate though.

-Jack Dahlgren

I just started a project and adopted a schedule with the below formula.
No one knows the intent of the formula which is in a Number Field...can
you guys help me decipher it?

Start is the 'Start Date'
Start 2 is the 'Status Date' (it's set every month)

I understand the first part says if the Status Date is more than one
month of the Start Date.

It's the part that follows I'm having a hard time deciphering.

Is the (1.946/7) and (1.82/7) a common formula in MS Project?

IIf((Start2-Start)>32,([Start2]-[Start])-((1.946/7)*(Start2-Start)),([Start2]-[Start])-((1.82/7)*(Start2-Start)))

Thanks for the help.

 

[Cole]

Thanks I think both of you are right.

The column is used in calculating a BCWS. I disagree with the whole
method but was ask to disprove their current system down to the
detail...LOL...gotta love work sometimes.

I agree there is a better way to do this and i'm going to do it.

Thanks for all your help.

Take a look at it.

The x/7 part surely refers to weeks and is subtracted from the complete
duration. In both cases x is almost 2 but is slightly less. I take this to
be some averaging on the part of whoever wrote the formula. I suspect that
in a month of 31 days there are an average of 31 - (1.82/7*31) working days.
When the duration gets longer then the average gets closer to duration -
(2/7 * duration). but doesn't quite reach there.

So in essence, the author of the formula took a basic formula of duration -
2 days for every 7 of duration and tweaked it to be more "accurate".
However, Project already offers a simpler, more accurate method of doing
this so I'd abandon this approach. What is that column titled? What is is
used for? That should give you the final clue you need to be 100% certain.

-Jack Dahlgren

Thanks Jack.

Weekends are not work days not sure if that makes a difference.. How
does the math part of the formula take out the weekends?

IIf((Start2-Start)>32,([Start2]-[Start])-((1.946/7)*(Start2-Start)),([Start2]-[Start])-((1.82/7)*(Start2-Start)))


Thanks for helping me understand.

Closest thing I can guess is that someone doesn't know how to do date
math
within project and is using those numbers to subtract weekends.
If that is the case simply rewrite the formula and use the projdatediff
function. The new formula would be:

ProjDateDiff([Start],[Start2],"standard")

The standard is an optional argument which names the calendar that should
be
used for the math. This way it takes into account whatever holidays you
have
entered as well.

For more information look here:
http://zo-d.com/blog/archives/progr...b-datediff-and-applicationdatedifference.html

Try it in a separate field and I think you will find the results are very
close to what the other formula gives. The formula I gave you is more
accurate though.

-Jack Dahlgren



I just started a project and adopted a schedule with the below formula.
No one knows the intent of the formula which is in a Number Field...can
you guys help me decipher it?

Start is the 'Start Date'
Start 2 is the 'Status Date' (it's set every month)

I understand the first part says if the Status Date is more than one
month of the Start Date.

It's the part that follows I'm having a hard time deciphering.

Is the (1.946/7) and (1.82/7) a common formula in MS Project?

IIf((Start2-Start)>32,([Start2]-[Start])-((1.946/7)*(Start2-Start)),([Start2]-[Start])-((1.82/7)*(Start2-Start)))

Thanks for the help.

 

[JD]

Don't be confused by the screen name. Both of them are me.
Glad it is working out for you.

-Jack Dahlgren

Thanks I think both of you are right.

The column is used in calculating a BCWS. I disagree with the whole
method but was ask to disprove their current system down to the
detail...LOL...gotta love work sometimes.

I agree there is a better way to do this and i'm going to do it.

Thanks for all your help.

Take a look at it.

The x/7 part surely refers to weeks and is subtracted from the complete
duration. In both cases x is almost 2 but is slightly less. I take this
to
be some averaging on the part of whoever wrote the formula. I suspect
that
in a month of 31 days there are an average of 31 - (1.82/7*31) working
days.
When the duration gets longer then the average gets closer to duration -
(2/7 * duration). but doesn't quite reach there.

So in essence, the author of the formula took a basic formula of
duration -
2 days for every 7 of duration and tweaked it to be more "accurate".
However, Project already offers a simpler, more accurate method of doing
this so I'd abandon this approach. What is that column titled? What is is
used for? That should give you the final clue you need to be 100%
certain.

-Jack Dahlgren

Thanks Jack.

Weekends are not work days not sure if that makes a difference.. How
does the math part of the formula take out the weekends?

IIf((Start2-Start)>32,([Start2]-[Start])-((1.946/7)*(Start2-Start)),([Start2]-[Start])-((1.82/7)*(Start2-Start)))


Thanks for helping me understand.

JackD wrote:
Closest thing I can guess is that someone doesn't know how to do date
math
within project and is using those numbers to subtract weekends.
If that is the case simply rewrite the formula and use the
projdatediff
function. The new formula would be:

ProjDateDiff([Start],[Start2],"standard")

The standard is an optional argument which names the calendar that
should
be
used for the math. This way it takes into account whatever holidays
you
have
entered as well.

For more information look here:
http://zo-d.com/blog/archives/progr...b-datediff-and-applicationdatedifference.html

Try it in a separate field and I think you will find the results are
very
close to what the other formula gives. The formula I gave you is more
accurate though.

-Jack Dahlgren



I just started a project and adopted a schedule with the below
formula.
No one knows the intent of the formula which is in a Number
Field...can
you guys help me decipher it?

Start is the 'Start Date'
Start 2 is the 'Status Date' (it's set every month)

I understand the first part says if the Status Date is more than one
month of the Start Date.

It's the part that follows I'm having a hard time deciphering.

Is the (1.946/7) and (1.82/7) a common formula in MS Project?

IIf((Start2-Start)>32,([Start2]-[Start])-((1.946/7)*(Start2-Start)),([Start2]-[Start])-((1.82/7)*(Start2-Start)))

Thanks for the help.