Calculating the nearest political party

EU&I shows the overlap between the parties’ positions and the users’ preferences. In order to simplify the interpretation of the results, the latter are expressed in terms of a percentage of overlap. 0% indicates that a political party and a user’s preferences do not overlap at all, 100% indicates that they completely overlap.
Technically, for calculating the overlap, we use the so-called “Manhattan (or ‘city-block’) distance”, which expresses how close two respective points are one from another in an n-dimensional space.
At the heart of EU&I lies a series of political or policy-related short arguments – the statements – on which it is possible to take a position. For example, EU&I asks users to take a position regarding the statement " Taxation on the wealthiest part of the population should be increased". Users can reply with one of the following answer categories: 'Completely agree', 'Tend to agree', 'Neutral', 'Tend to disagree' or 'Completely disagree'. EU&I also allows users to choose the option 'No opinion', which means that the statement is excluded from the calculation.  
For calculating the overlap, we first translate the answers given by the users into numbers, using the following criteria:

Completely disagree = 0
Tend to disagree = 25
Neutral = 50
Tend to agree = 75
Completely agree = 100

The same values were given to the positions taken up by the parties. We then calculate the distance between the positions of each user and political party on every statement, and then the average matching percentage across all the statements. The result is a rank-order list of all parties, each of them associated to a percentage, from the highest (best matching) to the lowest.

Calculating the nearest political party in Europe

Users have the additional possibility of matching their views with all the political parties included in EU&I 2024 in two ways: first, they can consult a list of party matches grouped by countries. Second, they can simply consult the full list of party matches. The calculation method for these Europe-wide visualisations is identical to the overlap calculations of the nearest party.

Calculation of uni-dimensions

Every statement can have some effect on one uni-dimensions. The resultant effect is defined with values: 1 (positive polarity), -1 (negative polarity). Positive polarity means that only positive answers (75-100) increase the value and negative polarity means that only negative answers (0-25) increase the resulting value. Statements with polarity 0 are not included in a uni-dimension calculation.
The resulting value regarding all answered questions for a political party or user can vary from 0 to 100, where 100 means total agreement.

For example, if five statements pertain to the uni-dimension “Ecological”, the first one has a polarity value of -1 for the dimension and the remaining four have a polarity of 1, the user has to answer “Completely disagree” to the first one and “Completely agree” to the remaining four statements to get maximum score on the dimension (i.e., be placed on the right end of the economic growth/environmental protection continuum).

Users should be aware that the uni-dimensions serves as an illustrative tool that provides an overview of the political parties and their views on these specific dimensions alone.

Political Landscape

The political landscape is based on similar assumptions as the uni-dimensions, but goes a step further. Namely, while the uni-dimensions represent the political spectrum in single, separate dimensions, the political landscape further reduces the complexity of politics and offers only two major dimensions: a European integration, pro-EU/anti-EU dimension (vertical axis) and a sociocultural-economic left-right dimension (horizontal axis).

Both of these dimensions range from zero to one hundred. In order to determine the position candidates and users in this two-dimensional space, their respective coordinates on the X and Y axes need to be calculated.

The initial position of a political party on an axis is 50% (neutral). Its position on an axis is calculated over all statements pertaining to that dimension, using the same formula as the uni-dimensions.

The political landscape representation is based on the assumption that, in most political systems, citizens’ and political parties’ opinions on individual issues can be aggregated to a limited number of issue dimensions. In the graphical representation offered to the user, the position of parties (and of the user) on each axis is the average of all positions across issues pertaining to each dimension.

The computation of such averages, on each of the two axes, depends on a priori considerations, both in terms of which dimension an issue belongs to, and which side of the dimension a specific issue position belongs to.

Both the position of the user and the position of candidates are presented to the viewer as points in a two-dimensional space. Please note that this visualisation does not influence the “Party match” result. Also, five statements were included that do not pertain to any of the two dimensions of the political landscape, or any of the six dimensions of the uni-dimensions; therefore, these contribute to calculate the party matching percentage but do not influence the visualisation tools.