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Simultaneous fit with HistFactory

Hi,

I’d like to perform a simultaneous fit over different years of data-taking to measure the value of a shared parameter of interest using HistFactory but I can’t figure out how to practically implement it. Should I declare different instances of the “measure” class one for each year? I see in the documentation that a dedicated class HistFactorySimultaneous exists but it seems to me pretty similar to the standard RooSimultaneous.

Thanks,
Jacopo

Hi,

You should be able to combine several HIstFactory measurents to make a combined model.
This should be done automatically by the HistFactory given as input the different xml files defining the measurements and the channels.
If you have some trouble doing this, please share your code and files and I can have a look

Cheers

Lorenzo

Hi,

I managed to run the simultaneous fit by defining different channels for each year of data-taking, and adding the shared parameter to the corresponding sample of each channel with AddNormFactor.

Cheers,
Jacopo