Patent Bar Authority Guide ✓ Verified for MPEP Ninth Edition, Rev. 01.2024 (Nov 2024) Updated for 2026 Exam Window

35 U.S.C. 103 Obviousness Explained

Under 35 U.S.C. 103 and MPEP § 2141, a patent claim is unpatentable for obviousness if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date to a person having ordinary skill in the art (PHOSITA).

Key 2026 Takeaways at a Glance

✓ Every § 103 analysis rests on the four Graham v. John Deere factual inquiries—including objective evidence of nonobviousness (secondary considerations).
✓ A reference can only be used in a § 103 rejection if it is "analogous art" under MPEP § 2141.01(a) (same field of endeavor OR reasonably pertinent to the inventor’s particular problem).
✓ MPEP § 2145 lists classic unpersuasive applicant arguments tested on every Patent Bar Exam.

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Practice 35 U.S.C. 103 Practice Questions (Obviousness) (MPEP Rev. 01.2024 Cited)

Practice 35 U.S.C. 103 Practice Questions (Obviousness) → 50 Free Questions

The 4 Graham Inquiries & 7 KSR Exemplary Rationales (MPEP § 2141 & § 2143)

To establish a prima facie case of obviousness, an examiner must resolve the Graham factual inquiries and articulate a clear rationale with a reasonable expectation of success:

• Graham Inquiry 1: Determine the scope and content of the prior art (must be analogous art under § 2141.01(a)).
• Graham Inquiry 2: Ascertain the differences between the claimed invention and the prior art.
• Graham Inquiry 3: Resolve the level of ordinary skill in the art.
• Graham Inquiry 4: Evaluate objective evidence of nonobviousness (commercial success, long-felt need, failure of others, unexpected results, copying, skepticism of experts) under 37 CFR 1.132.
• KSR Rationales (MPEP § 2143): (A) Combining prior art elements according to known methods to yield predictable results; (B) Simple substitution; (C) Use of known technique to improve similar devices; (D) Applying a known technique to a known device ready for improvement; (E) "Obvious to try" (choosing from a finite number of identified, predictable solutions); (F) Known work in one field prompting variations; (G) Teaching, suggestion, or motivation (TSM) in the prior art.

Top 5 MPEP § 2145 Traps Tested on the Patent Bar

Memorize these five rules from MPEP § 2145:

Applicant Argument	USPTO / MPEP § 2145 Rule
"References cannot be physically combined"	Unpersuasive — Test is what the combined teachings suggest to PHOSITA, not bodily incorporation
"Reference A alone does not teach feature X"	Unpersuasive — One cannot show nonobviousness by attacking references individually where rejection relies on A + B
"Combining A and B destroys A’s intended purpose"	Persuasive! If proposed modification renders prior art unsatisfactory for its intended purpose or changes its principle of operation (MPEP § 2143.01(V)-(VI)), prima facie case fails
"Attorney argument proves unexpected results"	Unpersuasive — Arguments of counsel cannot take the place of factual evidence in the record
"Age of references proves nonobviousness"	Unpersuasive — Mere age of references (e.g., 40-year-old patent) does not defeat obviousness absent evidence of long-felt need

How This Topic Fits Into the 2026 USPTO Registration Examination Blueprint

Every question on the USPTO Patent Bar Exam traces directly back to three primary legal authorities loaded onto Prometric testing workstations: Title 35 of the United States Code (35 U.S.C. 101 Subject Matter Eligibility, 35 U.S.C. 102 Novelty & Prior Art, 35 U.S.C. 103 Obviousness, and 35 U.S.C. 112 Specification & Claims), Title 37 of the Code of Federal Regulations (37 CFR Parts 1, 11, 41, and 42), and the Manual of Patent Examining Procedure (MPEP Ninth Edition, Rev. 01.2024).

Prometric Exam Day Execution Checklist

During each 3-hour, 50-question Prometric session, you have exactly 3.6 minutes (216 seconds) per question. High-scoring candidates answer 35 to 40 questions on their first pass using memorized rules from MPEP 700, MPEP 200, MPEP 600, and MPEP 1800, and reserve the final 50–60 minutes to look up marked edge-case exceptions in the on-screen MPEP PDF viewer.

AIA vs. Pre-AIA & Deadline Verification Protocol

Before selecting an option on any Patent Bar question, run a three-point check: (1) check the effective filing date against the March 16, 2013 AIA transition date, (2) verify whether the deadline is extendable under 37 CFR 1.136(a) or non-extendable by statute (such as the 12-month provisional period, 6-month maximum reply cap, or 2-year broadening reissue rule in MPEP 1400), and (3) check whether the proceeding is before the examiner, the PTAB (MPEP 1200), or Ex Parte Reexamination (MPEP 2200).

To turn passive reading into a passing 70%+ score (63 out of 90 scored questions), pair this guide with active question drills in our Free 50-Question Practice Hub, review worked hypotheticals on our Example Questions page, and benchmark your lookup speed in the Timed Patent Bar Mock Exam Simulator.

Frequently Asked Questions

When does a prior art reference "teach away" under MPEP § 2145?

A reference teaches away when it criticizes, discredits, or otherwise discourages investigation into the invention claimed. However, merely disclosing more than one alternative or describing a claimed embodiment as "inferior" or "not preferred" does not constitute teaching away unless it criticizes or discredits the claimed solution.

Does optimization of a result-effective variable support a prima facie case of obviousness?

Yes. Under MPEP § 2144.05(II), where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation if the parameter was recognized in the prior art as a result-effective variable.