Using social media to measure intentions to move house

Is it possible to measure the intentions of people to move house without actually asking them about their plans? Statistics Netherlands (CBS) has researched this question at the Center for Big Data Statistics. On the instructions of the Ministry of the Interior and Kingdom Relations, CBS already asks about the intention to move in the WoON survey, which forms part of the ongoing housing research. Every three years, this survey uses a questionnaire to gather information on respondents’ current living situation, including satisfaction with their homes and living environments, and their housing needs.

The ministry has commissioned CBS to investigate the use of alternative sources, such as social media, to measure the moving intentions. This CBS study shows that it is possible to automatically distil the moving intentions from information in social media posts. This is not to say that these people actually will move house in the near future, or that these people’s intention of moving reflects the intention of moving among the population of the Netherlands as a whole. Because the results deviate from the trends established in surveys and registers, they are not considered suitable to replace this data.

Working method

Findings

All public tweets containing the words ‘verhuis’ and/or ‘verhuiz’ that were available between 1 January 2011 and the end of May 2018 were included in the analyses: over 1.9 million tweets. In total, more than 4.8 billion Dutch-language tweets were available during this period. These tweets were used to assess the development of a moving intention in that time. The model used to classify tweets as ‘includes intention of moving’ or ‘includes no intention of moving’ is considered sufficiently reliable to be able to identify the intention of moving.

Figure 1 displays the findings from the relative number of tweets containing an intention of moving in the period from January 2011 to May 2018 inclusive. The series clearly shows two periods in which there is a decrease in the number of tweets containing an intention of moving: from January 2011 to December 2013 inclusive, and from August 2014 to May 2018 inclusive. The intervening period shows an increase in tweets regarding the intention of moving. As well as conducting an analysis in time, it is also interesting to see whether there is a seasonal pattern. The analysis showed that there is no strongly visible seasonal pattern, although the number of tweets containing a moving intention is lower in the period around December.

On average, 133 tweets including a moving intention were found each day during the period analysed, which translates to around 930 per week. In total more than 1.7 million tweets were posted every day: around 12 million a week. This puts the percentage of tweets including an intention of moving at 0.008 per cent after rounding. The series of tweets including an intention of moving reveals a different trend from that of the total number of tweets. This means that in some way the data reflects something meaningful. The daily and weekly series show the same patterns over time. The question, then, is whether an unusual occurrence such as an intention to relocate can be picked up with sufficient accuracy from social media. For validation purposes, 1,000 randomly-selected, anonymised social media accounts were followed for two years. Half the people who tweeted during this period indicated at a certain point that they had actually moved house.

Figure 1. Relative number of tweets containing an intention of moving posted each day from 1 January 2011 to 31 May 2018 inclusive (the inset shows the data before applying the spline filter)