From 2007. Redfin actual data vs Redfin model. 

• Rent, Per Employee, Per Month; 
• Initial Per-Employee Equipment Cost; 
• Monthly Benefits, Per-Employee; 
• Annual Payroll Tax; 
• Quarterly Bonus Payout, as a % of the Total Possible; 
• Annual Payroll Increase for Existing Employees; 
• Percentage of Candidates for Which Redfin Paid a Recruiting Fee; 
• For Employees Recruited for a Fee, the Recruiting Fee as Percentage of Annual Salary; 
• Incremental Amount Paid to Contractors, as Percentage of Payroll; 
• Monthly Travel Costs, Per Field Employee; 
• Monthly Telephone Costs per Field Employee; 
• Monthly Legal Costs; Annual Accounting Costs; 
• All-Company Meeting Cost, Per-Meeting, Per-Employee