Erin Osterhaus over at Software Advice has released their 2014 Job Board survey of a 150 recruiters in cooperation with Recruitment Process Outsourcing Association (RPOA) and the National Human Resources Association (NHRA). 
It has some really solid and actionable data on the effectiveness, specifically the ROI, associated with posting jobs to the larger national boards including: LinkedIn, CareerBuilder, Indeed, Monster, Craigslist & Glassdoor.

Study highlights include:

• Overall LinkedIn Delivers the highest combination of Quality and Quantity of applicants at a median cost
• Indeed Delivers the Highest Quantity of applicants of any of the boards
• Indeed is the most useful for Entry-Level positions while LinkedIn leads for both Mid & Senior-Level jobs
• Craigslist Is the Least Expensive by a good margin and tied with CareerBuilder for second place when it came to delivering entry-level candidates

View the complete study at Software Advice