Common mistakes that lead to improper joinder include lumping unrelated claims or defendants into one complaint without a transactional or factual nexus, conflating separate legal theories that require different evidence, pleading speculative or jurisdiction-defeating parties (fraudulent joinder), failing to check venue and jurisdictional rules before filing, and careless boilerplate language that unintentionally expands scope; the best lawyers address these errors by performing a careful pre-filing audit of claims and parties, mapping each cause of action to concrete facts and damages, confirming jurisdiction and venue, using targeted pleadings (and avoidance of broad catch-alls), and—if misjoinder is discovered—acting quickly: meet-and-confer to narrow or amend, then file a motion to sever/dismiss or move for remand as appropriate, seek case-management orders (bifurcation, limited discovery) to prevent prejudice, and preserve the record for appeal while documenting their step-by-step reasoning as a best practice.
