Public spending is often a contentious subject because different political parties have different agendas as to what should be the current national priorities. Of course, the same is true for the public in general. It is thus of interest to determine whether public spending is indeed as biased and capricious as it is often perceived, or whether there nevertheless exist some fundamental principles that guide it. We use data from the Commission for the Prevention of Corruption of the Republic of Slovenia, detailing every transfer of public money to the private sector from January 2003 to May 2020. During this time Slovenia has done business with no less than 248,989 companies. We find that the cumulative distribution of money received per company can be reasonably well explained by means of a power-law or a log-normal fit. We also show evidence for the first-mover advantage, and determine that the attachment rate of public spending to companies over time is roughly linear. These results indicate that Slovenian public spending is to a large extent guided by self organizing principles that, against all odds, go beyond nefarious interests and lobbying.

Being a (relatively) small nation, Slovenia keeps excellent records of its public spending via the Commission for the Prevention of Corruption of the Republic of Slovenia (CPC).  It is an independent agency with a broad mandate to prevent and investigate corruption and other breaches of ethics and integrity, with a special focus on transparency of public spending.  CPC gathers the data from nine different public institutions in Slovenia, including the Ministry of Finance, Public procurement portal and Public Payments Administration. In particular, all private companies registered in Slovenia are under legal obligation to report the exact information on any business done using public funds. Hence, CPC keeps track of all transactions where public money is being spent on business with private sector. For transparency motives all this data is publicly available on the CPC website. Upon signing the adequate contract, we received this data set from the CPC. The received data set includes all public-to-private transactions from January 2003 to May 2020. During these 209 months, it turns out, Republic of Slovenia has done business (ordering services or buying goods) with exactly 248,989 companies. To avoid noise and uncertainties we excluded from further analysis companies that in this period made less than 10,000 EUR. This cut-off in total spending per company translates to 105,086 companies to which we focus in the analysis. In this matrix, each element is the amount of money (in EUR) that some company received from all public bodies during one of these 209 months. In other words, for any given company we have a time series with 209 values, each value representing the volume of business done using public funds overthat month. This data is possibly unique in the world. Its completeness and precision allows for examining the presence of self-organization, which is what we devote the rest of this paper to. Specifically, we find a heavy-tailed distributions of total public spending per company versus company rank that can be fitted reasonably well by a power-law.

Please see the README.md document and the accompanying published article: J. Joksimović,M. Perc and and Z. Levnajić (2023). Self-organization in Slovenian public spending. Accepted.