In general SCOUT computes absolute refletance or transmittance spectra with values between 0 and 1. If you want to compare simulated and measured spectra you must have also experimental data that are absolute. If you do not have absolute experimental spectra but only relative ones there are two ways to proceed in SCOUT.

One way is to normalize the relative experimental data using an appropriate correction spectrum to convert the data to absolute ones. The imported experimental data are multiplied automatically by the reference spectrum defined in the window that opens after the command Objects|Reference. You can apply a user-defined formula to  compute the reference spectrum or, alternatively, you can import the reference spectrum from a data file. If you have measured, for example, the reflectivitiy of a sample with respect to a reference mirror, you can import the absolute reflectivity of the reference mirror (which must be known from other experiments) into the reference window. Then, the imported relative data are multiplied with the reflectance of the reference mirror and converted to absolute reflectivities this way.

The second possibility is to compute relative spectra and compare them to relative experimental data. Of course, both quantities must be 'relative' in the same sense. An example is the following: In the experiment the transmission of a pure substrate is recorded as the reference, and then the transmission of a thin film deposited on that substrate is measured with the ratio of the two samples as experimental output. You might want to compare this ratio spectrum to the corresponding simulated ratio. To do this you have to proceed as follows: First, compute the absolute transmission spectrum of the blank substrate and store the spectrum to a data file, using the SpectraCalc format, for example. Then import this spectrum in the reference spectrum window. Set the content of the Manipulation edit box in the spectrum simulation window to 'Y(X,Y)=Y/REFERENCE' and activate Recalc. You should now obtain a simulated 1.0, since you are computing the ratio of the substrate transmission and the substrate transmission. Now modify the layer stack and compute relative transmission spectra which now can be compared to the measured ones.

If the Manipulation formula contains the keyword 'REFERENCE' it is assumed that you want to work with relative simulated spectra. In this case, the experimental data are not multiplied with the reference spectrum after import!