Hi, the cheatsheet chapter in the gretl user guide has a part about this subject. Apart from using the "markers" command, it proposes to use the stringify function in a second step. However, in section 16.2 of the same guide, under the heading of "Assigning from an array of strings" there's an example that also starts with the markers command, but then simply assigns the result to a series, as in "series state = S". I just verified in my own panel dataset that that worked nicely. (Full disclosure: My dataset only had the country codes in the observation markers, no panel-time information in there. That would have complicated things, I guess., But I think the same problem would apply to the first solution.) So the question is: Given that the second way feels more natural, is the solution in the cheatsheet outdated, or is it better in some other respect that I'm missing? thanks sven