https://onlinelibrary.wiley.com/doi/full/10.1111/1475-6765.12084

https://onlinelibrary.wiley.com/doi/full/10.1111/j.1475-6765.2006.00694.x

I would recommend to check some projects using these surveys (their researchers usualy validate the data), such as Electoral Integrity Project, Variations of democracy, or Chapel Hill expert survey, etc. - however, I would expect more positive evaluations of their results when testing their own data...

Dear Marek,

Hopefully, these articles will beneficial for you.

http://www.robertthomson.info/wp-content/uploads/2010/11/Budge_EJPR00_expert_judgements.pdf

http://www.noamlupu.com/Lupu_Michelitch_ARPS.pdf

http://www.scb.se/contentassets/ca21efb41fee47d293bbee5bf7be7fb3/evaluating-survey-questions-a-comparison-of-methods.pdf

http://aei.pitt.edu/79404/1/Lindstadt.Proksch.Slapin.pdf

https://digitalcommons.unl.edu/cgi/viewcontent.cgi?referer=https://www.google.com.pk/&httpsredir=1&article=1138&context=sociologyfacpub

Best of luck for your research.

Thank you so much for your recommendations!

Also V-Dem has recently published a working paper:

https://www.v-dem.net/media/filer_public/d0/b2/d0b2160c-07f8-4f80-9e04-8fe2ec67b5ba/v-dem_working_paper_2018_68.pdf

I remember, the European Journal of Political Research did publish an article on the role of expert judgements regarding elections in 2015