Why Glassdoor's Data Engineer Salary Is Wrong
Glassdoor uses a 36-month rolling average. That means the number you see today pulls salary submissions from 2023, 2024, and 2025 into a single figure. Think about what happened in 2023: hiring freezes, headcount reductions, comp compression across the board. That data is still in the mix, dragging the 2026 average down by 12 to 17%.
It gets worse. Entry-level and mid-level workers submit salary data at higher rates than senior engineers. Roles with complex comp structures (equity, bonuses, sign-on) are the least accurately reported. And Glassdoor's own methodology page admits it flags "low confidence" when data is old or sample sizes are small, but it doesn't prominently surface which data engineer entries fall into that bucket. You're negotiating blind.
Glassdoor also makes no retroactive inflation adjustment. A $140K submission from 2023 sits in the average at face value, not adjusted for the cumulative 8 to 10% inflation since then. So the algorithm treats a 2023 dollar the same as a 2026 dollar. That's not a rounding error; it's a structural flaw.
Self-reported salary surveys undercount by 7.3% on average when benchmarked against administrative wage data. The underreporting is worst among lower-income respondents, which is exactly the profile of recently laid-off workers rebuilding their careers.
Cross-reference against Levels.fyi and the picture looks completely different. Their median sits at $155K across all companies, with Google L3 to L6 ranging $164K to $358K and Meta IC3 to IC6 at $168K to $439K. LinkedIn's salary tool has a 10 to 15% accuracy advantage over Glassdoor on recency. The industry consensus is clear: cross-reference at least 3 sources before you anchor to anything.