CROss-National Online Survey (CRONOS) panel

Building on our previous experience of mixed mode research, ESS ERIC has been leading on the development of a Cross-National Online Survey (CRONOS) panel. CRONOS is the first attempt to establish a cross-national probability-based online panel following a harmonised approach throughout—from the recruitment stage to data processing. CRONOS is a pilot study to evaluate the effectiveness of panel recruitment on the back of an existing cross-national survey in terms of costs, sample representativeness, participation and attrition rates, and data quality. Although there is no intention to replace face-to-face data collection with an online survey in the near future, a follow-up online panel offers quick, flexible, cost-efficient and regular data collection from the same respondents over time.

CRONOS was designed and implemented alongside ESS Round 8 in 2016, as part of the larger SERISS project. After completing the ESS face-to-face interview, respondents in Estonia, Great Britain, and Slovenia who were 18 or older were invited to participate in six 20-minute online surveys over a time period of twelve months. Respondents who did not have internet access for private use were offered a tablet and internet provision for the duration of the project to enable their participation.

After following a harmonised recruitment approach, the CRONOS panel was managed centrally with continuous and crucial support from national teams. A central panel administration system was set up on Questback-EFS: waves were programmed, distributed and monitored centrally from this system. The national teams translated and adapted all source documents (respondent communications, survey questions), sent out postal and SMS communications, set up experiments, and maintained a helpline that panellists could contact for assistance or queries. In addition, national teams worked with the central team in the design of recruitment strategies and experiments.

Data collection took place between December 2016 and February 2018. After a short 10-minute welcome survey, waves 1 to 6 included around 100 questions on diverse topics, often borrowed from high-standard cross-national surveys (e.g., European Values Study, Generations and Gender Programme, International Social Survey Programme, European Quality of Life Survey).


CRONOS data and documentation

The following CRONOS datasets are available free of charge for non-commercial use (and can be linked to ESS Round 8 data):

CRONOS survey data

CRONOS correspondence data (contains information on the correspondence with panellists, for waves 2-6)

CRONOS administrative data (contains administrative information for CRONOS-eligible ESS8 respondents)

CRONOS paradata, including:


CROss-National Online Survey (CRONOS) panel: Data and documentation user guide’ provides information about the contents and structure of each dataset. CRONOS documentation including questionnaires and codebooks — as well as a detailed description of the panel methodology — are also available to data users and researchers.

The CRONOS team request that use of the CRONOS data should be acknowledged using the following form of words:

CROss-National Online Survey panel [NAME OF DATASET] (2018). NSD - Norwegian Centre for Research Data, Norway – Data Archive and distributor of CRONOS data for ESS ERIC.


CRONOS methodology

The CRONOS panel also served as a platform for research on survey panel participation and question pre-testing. The research focused on incentives and contact mode experiments to enhance higher participation, experiments seeking to motivate respondents to be as accurate as possible when completing the surveys, experiments on translation approaches, and numerous question wording experiments. Details on the experiments will be provided in a forthcoming document.

Additional details on the design and implementation of CRONOS can be found on the SERISS website, under Work Package 7.

For the time being, the CRONOS team at European Social Survey HQ is focused on analysing the CRONOS data. 

The current research primarily concerns the methodological considerations related to setting up a cross-national, probability-based online panel and the quality of the data obtained from the CRONOS achieved sample.

These ongoing studies look at:

External academics are also undertaking research based on CRONOS data. At the 2019 European Survey Research Association (ESRA) conference in Zagreb, Croatia (15-19 July), there will be three sessions in which some of this research will be presented: 



The CRONOS panel has been developed under Work Package 7 (WP7) ‘A survey future online’ of the project ‘Synergies for Europe’s Research Infrastructures in the Social Sciences (SERISS)’ and received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 654221. The CRONOS initiative was also supported by ESS ERIC Work Programmes (2015-2017) and (2017-2019).

Neither the European Commission nor ESS ERIC bears any responsibility for any use that may be made of CRONOS data.

The design and implementation of the CRONOS panel was centrally led and coordinated by researchers at ESS ERIC HQ (Ana Villar and Elena Sommer), the Norwegian Centre for Research Data, NSD (Didrik Finnøy, Bjørn-Ole Johannesen, and Linn-Merethe Rød), the University of Ljubljana (Nejc Berzelak), and CentERdata (Arnaud Wijnant). The central team worked closely with the three national teams.

The CRONOS national team in Estonia comprised Mare Ainsaar and Indrek Soidla (University of Tartu); in Slovenia Slavko Kurdija, Tina Vovk, May Doušak, Živa Broder and Rebeka Falle (University of Ljubljana); and in Great Britain Alun Humphrey, Emma Fenn, Matt Jonas, and Joanne Maher (NatCen Social Research).

Supporting the central and national teams were: