What's the difference?

Proof-reading...

Simple Copy Editing...

Substantive Line Editing...

... is checking and correcting:

• typographical errors
  
• omissions
  
• spelling
  
• grammar
  
• punctuation
  
• consistency
  
• spacing
  

...is checking and correcting:

• language
  
• logical structure
  
• clarity
  
• consistency and style
  
• layouts
  
• illustrations
  
• standardize notes, bibliographies, and reference lists
  

...includes Simple Copy Editing and also:

• Recommends and initiates changes 
• Improves clarity and flow 
• Eliminates repetition, clumsy wording, and convoluted sentence structure
• Rearranges sections where necessary  
• Other as discussed with client