The vast majority of pre-IPO companies focus on the Market Base Salary data and Base Salary Compa-Ratio (vs. Total Cash). This is because the majority of pre-IPO companies do not offer a bonus program to all their employees.
Bonus becomes a more prevalent compensation component (i.e., across the entire org) as a company matures (closer to IPO or after going public) when they are not only able to establish goals that don’t fluctuate as much throughout the year (that you’d align to bonus payouts), but also equity becomes less prevalent as a compensation component.