Can a site redesign negatively impact a company`s SERP?

Selected answers from the Dumb SEO Questions Facebook & G+ community.

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  Seyf Nasr: Make sure that your URL structure is consistent. If you’re going to change the URL structure make sure to do 301 redirects and make sure that the content on the site is relative to the keywords that you’re trying to rank for. This also includes your H1’s, H2’s, etc.
  
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  Chris Hannon: Seyf Nasr, thanks for all of that good info!
  
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  James Slattery: 100%. Keep page content, names and titles consistent..
  
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  Chris Hannon: James Slattery, are you saying that there is a 100% likelihood that the SERP will be negatively impacted?
  
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  James Slattery: nope - im saying theres a strong likelihood it will be affected, at the very least temporarily
  
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  Chris Hannon: James Slattery, o.k.
  
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  Josh Levenson: yep
  
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