Newbie here. I have been reading and going thru the book online. This is my first post, so I apologize in advance if I am giving too much, or not enough information.

I work for a dialysis company and am trying to create a report that will calculate the change in a patient's weight from one treatment day to the next.

I currently have the report setup with parameters where the user can request a date range of information.

The tables record the patient's pre-weight and post-weight for each treatment day.

I want the formula to calculate the difference between the pre-weight of the current day and the previous treatment's post-weight.

I created this formula:
{DIALYSUM.PRE_DIAL_WEIGHT_KG} - {DIALYSUM.POST_DIAL_WEIGHT_KG}

But that is comparing the pre and post weight from the same treatment date. I want the post to be from the previous treatment. This way we can see how much weight the patient gained or lost since their last treatment.

Patients typically have 3 treatments per week, either Mon-Wed-Fri or Tue-Thur-Sat if that matters.

Any help in figuring out how to specify the post wt. be for the previous treatment would be appreciated.

Thanks,
David

Sarah,

Thanks for your reply. You have me on the right track. I applied the "previous" function, but it is working the opposite way I want it to.

Here is an example of what I got after apply previous to the formula
{DIALYSUM.PRE_DIAL_WEIGHT_KG} - previous({DIALYSUM.POST_DIAL_WEIGHT_KG})

Date    Pre Wt     Post Wt       Wt Change
6/2/08   71.00       68.70       
5/30/08 70.80       69.05        2.10

The formula is taking the pre-weight from 5/30 and subtracting the post-weight from 6/2 giving the result of 2.10. (70.80 - 68.70 = 2.10.

Instead, I am trying to get the formula to take the pre wt from 6/2 (71.00) and subtract the post weight from 5/30 (69.05) to get the weight change on the 6/2 line to show as 1.95.

Is their a function opposite of previous, such as Next?


Edit..Update, their is a next function and that did the trick, replacing previous with next. Thanks again Sarah for your help.

Edited by dlabrec - 03 Jun 2008 at 10:52am