How to create probability functions in patient tracks?

Hello

I am currently using Flexsim HC to model a clinic. I was just browsing through the help function on patient tracks and found that it is possible to create tracks such that patients can move from one activity to a possible number of different activities, depending on the conditions set.

Perhaps describing my scenerio will give a clearer picture. In my model, after the patient arrives, he will proceed to register. After registration, he will either proceed to the

1.triage station followed by physician consultation
2.straight for physician consultation

How can I go about creating the branch off for the tracks? I tried using the advance functions for the registration activity, selecting the "next activity chooser" based on percentages. However, the result wasn't too good when I ran the program. The patient jumped between triage and physician consultation.

Would really appreciate if you could advise me on how to go about from here.

Thank you!

Best regards
Lionel

Hello,

the first thing that comes to mind is if you changed the predecessor activity on the "branches" of the track.. this was an issue for me the first time i tried using the next activity chooser option..

regards

Pablo Concha Erilkin

I know this doesn't answer your question but it might be a solution in some cases: have 2 tracks with the right % for the 2 options

Hi Pablo

Thank you for the response. I have actually assigned the right predecessor, but what happens is that when I assign the next activity by percentages under next activity chooser, both activities occur simultaneously, and not based on a probability percentage.

Under the addition of activities in Patient Tracks, do you know how to create sub branches from the branches (activities 10_, 20_, etc)? Something similar to what is shown in the help function under tutorials-modelling tools-track manager-activities.

Sorry for asking so many qns.

Lionel, sorry about the first response... i made that test a while ago and didn't remember what was the problem i had, it was the same you have now.

To solve it you have to make sure of 2 things,

1.- on the start of the branch (1st activity of the branch) use as predecesor the same activity number. so that that activity is it's own predecessor.

2.- be sure to update on advanced funtions the next area list on the activity where you are setting the activity chooser, so the connection are made correctly ( move to the right tha possible areas according to the activity chooser)

As Steven mentions, you also have the option to use 2 tracks and set the percentages on the PatientArrivals

regards

Pablo Concha Erilkin

regards

Pablo Concha Erilkin

Pablo

Thank you very much! The model is working now.

Best regards
Lionel

Pablo

When you built your model, did you come across global look-up tables? In the "Next Activity Chooser" option, under "by percentage", it is only possible to assign percentages for the first 5 activities. The instruction says that if there are more than 5 activities to be assigned, we have to use empirical tables. I assume it refers to global look-up tables. In the table, do I key in data identical to the format for percentages? And after I select the table in the "Next Activity Chooser" option, do I have to change any of the commands?

Best regards
Lionel

Lionel,

to use an empirical distribution (table), you have to create a table in wich the first column you asign the percentages and in the second the value you need to return (in this case, activity numbers), you can set as many rows as you need. Then when you need to use this distribution, you use the command dempirical("tablename").

in your case, i think you need to select the option "custom code" in the next activity chooser, the go to the edit code option (the big A button at side of the option) and change the 100 on the nextactivityID = 100; line so that it reads:

nextactivityID = dempirical("tablename");

regards

Pablo Concha Erilkin

The picklist option "By Percentage" has been improved for the next release so that there is not a limit to the number of percentage that can be defined. It also has an easier template view for entering the data.

I've also made a function called P() which can take up to 30 parameters in the order of percentage, value, percentage, value, etc. This was done in response to a request by a user for a single command that can be easily imported and exported via the csv file option for tracks.

Before deciding to branch a track, I suggest you consider how you want it reported.

I believe that if you branch a track, the results of each branch are aggregated and remain within that track; in some cases, overall results may be misleading.

If you simply use two different tracks with the right % in each, then each one gets its own space in the track-by-track statistical comparisons.

Neither is right or wrong, just appropriate for purpose.

Kenny