Ethereum: Why was it decided to adjust the complexity every 2 weeks (and not every 2 days or every few blocks)?

Ethereum Difficulty Adjustment: A Complicated History

When Ethereum first launched in 2015, its developers decided to adjust the difficulty every two days. However, this decision has been a subject of debate among users and analysts for years. In this article, we explore why the 2-week difficulty was chosen and whether there are any benefits to adjusting it more frequently.

Early days: 2-day adjustment

At launch, Ethereum had a block time of 15 seconds (or 1 block per day). As the network grew, so did its ability to handle increasing transaction volume. The developers wanted to ensure that the network would scale without bottlenecks and network congestion issues.

The two-day adjustment period was chosen as a compromise between providing sufficient mining incentives and minimizing the impact on the overall network performance. By adjusting the difficulty every day, miners would have a relatively consistent incentive to confirm transactions, even if it meant slower block times. This allowed some flexibility in handling small fluctuations in network conditions and gave developers the ability to fine-tune difficulty adjustments as needed.

Advantages of the 2-week adjustment

So why was 2 weeks chosen instead of other adjustment periods? The main advantage is that this allows for a gradual adjustment of mining incentives, which can help mitigate the effects of network congestion. With less frequent block time changes, miners are better able to adapt to small fluctuations in network conditions.

Another advantage is that this period provides developers with breathing space to make changes to their mining hardware and software as needed. The slower adjustment process allows them to take time to test and improve new hardware or optimize existing settings without causing significant disruption to the entire network.

Disadvantages of More Frequent Adjustments

On the other hand, there are some disadvantages to adjusting the difficulty every 2 days (or every few blocks):

• Increased Variability: When block times are changed more frequently, miners are exposed to greater variability in transaction processing times. This can increase latency and degrade user performance, especially when processing high-frequency transactions.

• Reduced Mining Incentives: More frequent adjustments can reduce miners’ incentives to invest time and resources in optimizing their hardware and software. As a result, they may be less motivated to participate in the validation process, leading to a decrease in overall network performance.

Current Paradigm: 2-Week Adjustment

In recent years, Ethereum developers have gradually moved towards adjusting every 4 weeks (or roughly every few blocks) instead of daily or bi-dayly. This change is intended to maintain a more consistent and predictable block time, while still allowing some flexibility to handle small fluctuations.

By reducing the frequency of adjustments, the network is better able to cope with changing conditions, such as increased transaction volumes or reduced network congestion. In addition, this period provides a smoother transition between different mining algorithms and hardware configurations, which can lead to better overall network performance.

Conclusion

The decision to adjust Ethereum’s difficulty every two weeks (or roughly every few blocks) has been driven by a combination of technical factors, including the need for gradual adjustments, reduced volatility, and increased mining incentives. While more frequent adjustments have their drawbacks, the current paradigm offers a better balance between predictability and adaptability.

As the network continues to evolve, it is likely that future changes will be made based on ongoing analysis and testing.