Table 1.
Overview of individual-level features.
Source: Author’s own work
| Variable name | Type | Original coding | Nbr. of missing values | Recent studies finding a significant effect of this determinant | |
|---|---|---|---|---|---|
| Demographic | Gender | Binary | 0: male; 1: female | 0 | Elek and Köllő (2019), Franic and Cichocki (2021), Gregorio and Giordano (2016), Hofmann et al. (2017), Popescu et al. (2016), van Dijke and Verboon (2010), Williams and Horodnic (2015a, b) |
| Age | Interval | Values representing exact age | 0 | Elek and Köllő (2019), Gregorio and Giordano (2016), Hofmann et al. (2017), Popescu et al. (2016), Williams and Horodnic (2015a, b), Windebank and Horodnic (2017) | |
| Marital status | Categorical | 1: (re-)married without children; 2: (re-)married with children from this marriage; 3: (re-)married with children from a previous marriage(s); 4: (re-)married with children from this and previous marriage(s); 5: cohabiting without children; 6: cohabiting with children from this union; 7: cohabiting with children from previous union(s); 8: cohabiting with children from this and previous union(s); 9: single without children; 10: single with children; 11: divorced/separated without children; 12: divorced/separated with children; 13: widowed without children; 14: widowed with children | 164 | Alm et al. (2016), Arendt et al. (2020), Franic and Cichocki (2021), Gregorio and Giordano (2016), Popescu et al. (2016), Strielkowski and Čábelková (2015), Williams and Horodnic (2015a, b) | |
| Household size | Interval | Values representing the exact number of persons in a household | 2 | Arendt et al. (2020), Williams and Horodnic (2015a, b), Williams et al. (2015a, b) | |
| Socio-economic | Type of community | Categorical | 1: rural area; 2: town or suburb/small urban area; 3: city/large urban area | 0 | Boone et al. (2013), Popescu et al. (2016), Williams and Efendic (2021) |
| Country of residence | Categorical | Values designating in which of 27 member states an individual lives | 0 | Franic and Cichocki (2021), Kayaoglu and Williams (2017), Williams et al. (2015a) | |
| Migrant worker | Categorical | 0: individual does not work abroad; 1: individual works in another EU member state; 3: individual works outside EU | 0 | Gregorio and Giordano (2016), McKay (2014), Porthé et al. (2010), Rodgers et al. (2019), Williams and Efendic (2020) | |
| Age when finished education | Categorical | 1: up to 15 years; 2: 16–19; 3: 20 years and older; 4: still studying; 5: no full-time education | 409 | Arendt et al. (2020), Boone et al. (2013), Elek and Köllő (2019), Gregorio and Giordano (2016), Hofmann et al. (2017), van Dijke and Verboon (2010), Williams and Horodnic (2015a, b) | |
| Occupation | Categorical | 1: houseperson; 2: student; 3: unemployed, temporary not working; 4: retired, unable to work; 5: farmer; 6: fisherman; 7: professional (lawyer, etc.); 8: owner of a shop, craftsman, etc.; 9: business proprietor; 10: employed professional (doctor, etc.); 11: general management; 12: middle management; 13: employed position, et desk; 14: employed position, travelling; 15: employed position, service job; 16: supervisor; 17: skilled manual worker; 18: unskilled manual worker | 0 | Franic and Cichocki (2021), Gregorio and Giordano (2016), Kayaoglu and Williams (2017), Strielkowski and Čábelková (2015), Williams et al. (2015a), Windebank and Horodnic (2017) | |
| Size of the company | Categorical | 0: not working or self-employed without workers; 1: 1–4 employees; 2: 5–9 employees; 3: 10–19 employees; 4: 20–49 employees; 5: 50–99 employees; 6: 100–499 employees; 7: 500 + employees | 772 | Elek and Köllő (2019), Franic and Cichocki (2021), Popescu et al. (2016), Vallanti and Gianfreda (2020), Williams et al. (2015a) | |
| Financial difficulties | Categorical | 1: most of the time; 2: from time to time; 3: almost never/never | 388 | Arendt et al. (2020), Boone et al. (2013), Hofmann et al. (2017), Popescu et al. (2016), Williams and Efendic (2021), Williams and Horodnic (2015a, b), Williams et al. (2015a, b) | |
| Social class (self-assessed) | Categorical | 1: working class; 2: lower middle class; 3: middle class; 4: upper-middle class; 5: higher class | 868 | Williams et al. (2015a, b), Williams and Horodnic (2015a), Williams and Horodnic (2017b) | |
| Perceptions and attitudes | Perceived detection risk | Categorical | 1: very high; 2: fairly high; 3: fairly small; 4: very small | 2685 | Arendt et al. (2020), Elek and Köllő (2019), Franic and Cichocki (2021), van Dijke and Verboon (2010) |
| Expected sanction if caught in undeclared work | Categorical | 1: normal tax or social security contributions due; 2: normal tax or social security contributions due, plus a fine; 3: prison | 3408 | Fegatilli (2009), Feld and Larsen (2012), van Dijke and Verboon (2010) | |
| Any undeclared workers in social circle | Binary | 0: No; 1: Yes | 1172 | Horodnic and Williams (2019), Kayaoglu and Williams (2017), Williams and Öz-Yalaman (2021) | |
| Estimated % of population engaged in undeclared work | Categorical | 1: less than 1%; 2: 1–5%; 3: 6–10%; 4: 11–20%; 5: 21–30%; 6: 31–40%; 7: 41–50%; 8: more than 50% | 5203 | Alm et al. (2017), Franic and Cichocki (2021), Jimenez and Iyer (2016), Williams (2019), Gërxhani and Wintrobe (2021) | |
| Trust in tax authorities | Binary | 0: No; 1: Yes | 2640 | Alm et al. (2010), Kogler et al. (2015), Rodrigues (2020), van Dijke and Verboon (2010) | |
| Trust in labour inspectorate | Binary | 0: No; 1: Yes | 2894 | Kogler et al. (2013), van Dijke and Verboon (2010) | |
| Tax morale | Interval | Values from 1 to 10, where larger numbers represent lower tax morale | 1424 | Franić (2020), Franic and Cichocki (2021), Jimenez and Iyer (2016), Williams and Horodnic (2015a, b), Windebank and Horodnic (2017) |
(i) To enhance training and increase predictive power, all categorical variables were recoded into a set of binary indicators, while interval variables were normalised
(ii) Missing values were imputed through an iterated round-robin procedure based on Bayesian ridge regression