Human development index? Assuming higher values are indicative of lesser inequality.

What about housing/neighborhoods where people live? schools/education or employment?  Actually, it is difficult to separate any of these with income and as indicators of inequality. What about omitting the income factor or measuring its impact separately?

In order to determine socioeconomic inequalities, I usually prefer the variables related to the profession and education level. They are indicators with degree of fidelity far superior to the income indicator

This sounds like a perfect research question for multilevel modelling (citizens nested within countries). Using HLM, you could model citizens at level-1 and countries at level-2. This should alleviate concerns about using income-based measures at both levels. In fact, multilevel models often include within-variable aggregates at level-2. For example, individual income at level-1 and average income at level-2. In this case, individual income would be used to explain within-group variance in your outcome while average income would explain between-group variance in the outcome. However, this is based on the assumption you have adequate variance in your outcome at both levels.

Inequality is experienced at both absolute and relative levels.  Is your data spatially explicit?  If so, you could compare the income and household characteristics of your participants with background census data.

I love all this responses. I add to you health indicators, such as women death around marriage and maternity ages. 

Good question, Maddalena.

In general terms, I think you can disentangle a number of the good suggestions above by switching attention from Income (whether financial or of other types) to a clearer focus on the assessment of Assets.

Consider: Assets can be seen as accumulated consequences of Income.

At the material level, one might invest some income in property, or in a vehicle to assist in one's earning* 

One can also invest, as mentioned above in earlier Answers, at a non-material level, e.g. in education, or in health-related ways, to build the Asset of human capital.

While both Income and Assets can either be looked at as snapshots at one instant, or as time-series over a range of time, I suggest that there are multiple benefits to using Assets (versus the use of Income) as their accumulated - or dissipated - value, at one time, relates also to the income level over a range of the preceding time (the "integral", to put it in quantitative terms).

While I cannot suggest a particular index for Assets, one way to start the analysis for this research could be to build a small  "influence diagram" that allows you to assess, consistently, the main involved "stocks and flows" (flows of Income (and corresponding outgoings) and resulting changes in stocks of Assets (and any wastage or diminution in the Assets)).

If anyone is interested to model this more quantitatively, they might want to look into the approach of  System Dynamics (look up Jay W,. Forrester** and John Sterman, both M.I.T. (the Wiki site for SD is now a bit heavy-going for an introductory view).  

However, the John Sterman Introductory YouTube link may give anyone interested a taste of it.

Hoping this helps - Paul 

* particularly in developing countries - see Hans Rosling's TED talks about the impact of gaining a bicycle or a moped, for near-subsistence farmers to access markets efficiently,

** Incidentally, Forrester died just a fortnight ago, at the age of 98. 

https://www.youtube.com/watch?v=V3pPQk5Opc8

I'm far from an expert,  but Assets would probably be a good factor. Maybe credit score? In the US, credit score is a function of many variables, but also the predictor of asset accumulation. Just a thought. 

Ryan

Thanks for that.

According to Investopedia, the FICO (the most commonly used in US, also used worldwide) does not include income information.

FICO seems to focus largely on credit-related factors in a person's financial history. Unfortunately, it doesn't seem to say much, if anything at all, about assets either.

Huffington Post has a short pieces about credit scores in a number of countries; Wikipedia says a bit more about it, but none of it seems to talk about assets.

Maybe estimating net worth would be easier, at least at an aggregated level. But getting people to answer (and do so truthfully) about their major assets - house value, savings and investments, car etc, might be rather error-prone.

http://www.investopedia.com/ask/answers/05/creditscorecalculation.asp

http://www.huffingtonpost.com/creditcom/how-do-credit-scores-work_b_1723362.html

https://en.wikipedia.org/wiki/Credit_score

http://www.investopedia.com/terms/n/networth.asp

Maddalena,

Further, in case the Assets approach is of assistance, the following [my bold etc] has reached me, from R-G member  Alexander Dill

"World Social Capital Monitor

About: 

Revaluation of around 173 countries, their regions, their culture, their assets, their potentials - that's my task since 2007 when I published my "Global Freeware Index" for the first time.

Today I evaluate the major global indices, their unilaterism and their bias. And I'm testing new evaluation methods without aggregated data and binary questions.

I hope that the new method will not only being accepted and used but as well giving a new chance to countries in crises and conflicts."

Hoping this helps - Paul

https://www.researchgate.net/profile/Alexander_Dill3

Could the person who's down-voted the preceding post please indicate a reason? (Message me, if you prefer to do so privately.)

I've briefly checked out Dr Dill's own site and while I've not looked specifically for a table of assets for European countries (for the OP's research), his work looks quite serious and worthy of respect, as far as I can tell.

Am I missing something? 

 (I can well afford a single downvote myself, and am interested only in whether there's some reason to dismiss Alexander Dill's work).

https://www.globalinnovationexchange.org/users/alexanderdill

Dr. Ellis, thank you very much for your time and help, I will try to use your suggestions and look at Dill's work, hoping to have the necessary data to actually be able to perform some regressions.

Thinking some more about your question, as well as the comments on assets and capacities - perhaps it would be useful to look at various disaster and/or livelihood stress indices for some ideas?  Often, these will incorporate factors such as land tenure, ecosystem service access (good land, etc.) and other not-so-strictly economic variables. For your study, perhaps it would be useful to look at things like access to equitable/non-hostile cross cultural experiences (e.g. travel), foreign language ability, perceived social status ("working class", etc.) and feelings of access to mainstream political and/or cultural systems of expression?