An Empirical Evaluation of Smart Contract-Based Data Quality Assessment in Ethereum

The data carried by transaction payloads play a crucial role in smart contract-based blockchain systems. Therefore, blockchains should be equipped with mechanisms to control their data quality. In practice, however, such mechanisms are currently missing. While in our previous work we have proposed how data quality controls can be implemented as smart contracts, in this paper we focus specifically on the evaluation of their execution overhead (time and cost). Evaluating this overhead is crucial to understand in which situations the cost of controlling the data quality of transaction payloads can be sustained by a blockchain system. We have implemented in Ethereum two pseudo-real scenarios that cover all the types of data quality controls in blockchains that we defined in our previous work and evaluated for each of them the time and cost overhead. The results show that the overhead of control can be high particularly for controls involving oracles that fetch off-chain data and controls that require to correlate data from different transactions.