# A Framework to Understand Attitudes towards Immigration through Twitter
## 2 Background
### Theories and Measurement of Attitude Formation  
Two theoretical models are often used to describe the formation of attitudes towards immigration. These are the Intergroup Contact Theory (ICT) [28] and the Integrated Threat Theory (ITT) [29; 30]. ICT explains how _positive_ attitudes form, while ITT describes how _negative_ attitudes are created.  
The ICT postulates that increased social interaction among people from different population subgroups reduces prejudice and enhances trust. The theory is based on conditions such as common goals for different groups and the benefits of cooperation and support (both formal and informal) to reach those goals. Existing research has contributed evidence to support these arguments [31; 32; 33]. Increased intergroup interaction reduces fear and anxiety that may exist when people interact with individuals from an unfamiliar group [34; 35] by promoting empathy and understanding [36; 37].  
In contrast, the ITT predicts that social interaction among people from different groups may lead to perceptions of threat and contempt toward members of the different groups [29; 30]. Two types of threat describe the formation of negative attitudes: symbolic and realistic. In the context of migration, these threats are related to competition in the labour market, to public health concerns from possible diseases, to increased crime and physical well-being, and to perceptions of the size of the foreign group, among others [38; 39], as well as an increased fiscal burden [40].  
The common method to measure attitudes toward immigration is to use public opinion survey data. Some examples include the Gallup World Poll, the Pew Global Attitudes Survey, the International Social Survey Programme, the World Values Survey, the Iposos Global Trends, the European Social Survey, and the Eurobarometer [41]. Data from the Gallup World Poll revealed that in all major regions of the world, people are more likely to want immigration to remain at the current level or increase, rather than decrease, with the exception of Europe. However, there is great variability between countries. In Europe, for example, southern Europeans tend to show more negative attitudes towards immigration than northern Europeans, who show more positive attitudes [4].  
Although there is now a large repository of public opinion surveys on migration, some important limitations with these traditional methods arise. For example, existing surveys are mainly from European and North American countries, the number of questions collecting opinions on migration is highly variable across countries, their frequency is coarse, and they are often costly to implement. Thus, it has become a necessity to obtain frequent, comprehensive information covering different regions of the world to understand attitudes toward immigration, as stated in the first objective of the Global Compact for Safe, Orderly and Regular Migration: \"to collect and use accurate, disaggregated data to formulate evidence-based policies\" [9].  
In this work, we propose that the discussion in social networks offers a novel and inexpensive source to complement traditional data systems. It can be collected in near real-time, which would allow for richer analyses grounded on the aforementioned theories. In the following, we describe the potential of the social network Twitter in this regard.