Is highlighting an effective study technique for certification exams?
Highlighting alone is low-utility. Research consistently shows it produces minimal retention benefit compared to active strategies because it requires no cognitive processing beyond recognition. However, highlighting combined with annotations -- brief marginal notes explaining why something is important or how it connects to other concepts -- is substantially more effective. The annotation is the learning event; the highlighting is organizational.
Highlighting is among the most universal and least effective study strategies when used alone. The act of moving a marker across text requires only that you recognize important-seeming content -- no retrieval, no processing, no generation required. Yet most candidates use highlighting as a primary review strategy, re-reading highlighted text as if it were a summary.
This guide distinguishes between highlighting as an organizational tool (useful) and highlighting as a learning strategy (insufficient), and establishes annotation practices that make text marking genuinely valuable.
Why Highlighting Alone Is Low-Utility
Research by Dunlosky et al. (2013) categorizes highlighting and underlining as low utility strategies:
"Highlighting and underlining are among the most popular study strategies but among the least effective for improving long-term retention. They require minimal cognitive effort, do not produce the generative processing needed for durable encoding, and create an illusion of learning through familiarity that does not translate to retrievability." -- Dr. John Dunlosky, Department of Psychology, Kent State University
The fundamental problem: highlighting converts passive reading into passive reading-with-color. The cognitive demand is unchanged. The material that feels significant is marked, but the marking itself does not engage memory encoding processes.
The Role of Highlighting as Organization, Not Learning
Highlighting is useful as an organizational tool with a different purpose: identifying where to return for deeper study or annotation.
Effective use of highlighting for organizational purposes:
- Mark content you do not yet understand (flag for deeper study, not for re-reading)
- Mark content you want to create a flashcard from (flag for flashcard creation)
- Mark content that contradicts your prior understanding (flag for reconciliation)
With this framing, a highlighted passage is not "I have studied this" but "I need to do something with this."
Annotation: The Upgrade That Makes Marking Effective
Annotation -- writing in the margin or digitally noting your response to the text -- produces substantially better retention than highlighting alone because it requires active processing.
Types of annotations and their cognitive value:
| Annotation Type | Example | Cognitive Process |
|---|---|---|
| Self-questioning | "Why does this require a PKI rather than symmetric keys?" | Elaborative interrogation |
| Connection note | "This is why TLS uses asymmetric for key exchange but symmetric for bulk data" | Relational encoding |
| Confusion flag | "This contradicts what the practice exam said about X" | Metacognitive monitoring |
| Application note | "We implemented this at work incorrectly -- I now understand why" | Concrete grounding |
| Memory cue | "HMAC = integrity, not confidentiality" | Retrieval anchor |
| Summary annotation | One-sentence summary of a long paragraph in your own words | Generative processing |
Each annotation type requires more active processing than highlighting. The summary annotation, which requires you to identify the main point and rephrase it, is particularly powerful because it combines active recall with elaborative encoding.
Practical Annotation Techniques
The Margin Summary Method
After each paragraph or section, write a one-line summary in the margin in your own words. This is the highest-value annotation practice:
- Forces you to identify the main point
- Requires rephrasing (generative processing)
- Creates a scannable margin review later
The Question Annotation
At the start of a section, write a question the section should answer. At the end, write whether it was answered and how. This activates prior knowledge, focuses reading attention, and produces a comprehension check.
The Connection Annotation
When you encounter content that connects to something you already know, note the connection. "This is similar to X because..." or "This differs from Y in that..." Explicit connection annotations encode the relational structure of the domain.
Digital Annotation Tools
For digital study materials (PDFs, e-books, web content), annotation tools allow highlighting and note-taking without paper:
| Tool | Best For | Notable Feature |
|---|---|---|
| Notability (iOS) | PDF annotation with handwriting | Audio + ink sync |
| GoodNotes | Handwritten digital notes | PDF annotation |
| Adobe Acrobat | Standard PDF annotation | Cross-platform |
| Hypothes.is | Web content annotation | Shareable annotations |
| Kindle highlights | E-book annotation | Exportable highlights |
The same principles apply in digital contexts: annotation is the learning event; highlighting is organizational. Limit highlighting to 10-15% of text per section, and ensure each highlighted segment has an associated annotation.
The 10% Rule
A useful discipline for preventing over-highlighting: limit highlighting to 10% of any page or section. If you are highlighting more than that, you are not identifying the most important content -- you are marking everything that seems significant, which defeats the purpose.
When you must select only 10% to highlight, you make a judgment about relative importance. That judgment is itself an active cognitive process.
Frequently Asked Questions
If I should not re-read highlights, what should I do with them during review? Use highlights as prompts for active recall. Cover the highlighted text and attempt to recall the main point. Then reveal and check. Alternatively, use highlighted passages as prompts to create flashcards or as topics for the teach-back method. The highlight is a flag; the review activity is the learning.
Is it worth buying printed study guides just to annotate them? For major certifications requiring 3-6 months of study, printed annotated study guides are a worthwhile investment for candidates who process better on paper. The marginalia accumulate into a personalized reference that reflects your specific understanding gaps and connections. Digital annotation in PDFs achieves the same result with more flexibility.
Can I use color-coding in my highlighting to add meaning? Yes. Color-coding (green = definitions, yellow = processes, orange = exceptions, red = concepts I am uncertain about) adds an additional layer of organization. This is useful only if you apply the colors consistently and use them to guide differential review (spending more time on red-marked content than green).
References
- Dunlosky, J., Rawson, K.A., Marsh, E.J., Nathan, M.J., & Willingham, D.T. (2013). Improving students' learning with effective learning techniques. Psychological Science in the Public Interest, 14(1), 4-58.
- Fowler, R.L., & Barker, A.S. (1974). Effectiveness of highlighting for retention of text material. Journal of Applied Psychology, 59(3), 358-364.
- Nist, S.L., & Hogrebe, M.C. (1987). The role of underlining and annotating in remembering textual information. Reading Research and Instruction, 27(1), 12-25.
- Craik, F.I.M., & Lockhart, R.S. (1972). Levels of processing: A framework for memory research. Journal of Verbal Learning and Verbal Behavior, 11(6), 671-684.
- Pressley, M., McDaniel, M.A., Turnure, J.E., Wood, E., & Ahmad, M. (1987). Generation and precision of elaboration: Effects on intentional and incidental learning. Journal of Experimental Psychology: Learning, Memory, and Cognition, 13(2), 291-300.
- Bretzing, B.H., & Kulhavy, R.W. (1979). Notetaking and depth of processing. Contemporary Educational Psychology, 4(2), 145-153.