Tense consistency requires that a writer maintain a consistent time frame throughout a piece of writing unless a deliberate shift is needed. The sequence of tenses governs how the tense of a dependent clause relates to the tense of its main clause (She said that she was leaving vs. She says that she is leaving). Unnecessary tense shifts are a common source of reader confusion in student writing.
Edit passages with intentional tense errors, identifying each shift as either justified (a genuine change in time frame) or erroneous. Practice transforming present-tense narratives to past tense and vice versa to build flexibility.
You already know that verb tense locates events in time — past, present, or future — and that English has a rich system for expressing not just when something happened but its relationship to other events. Tense consistency takes this one step further: it asks you to maintain a stable temporal frame across an entire piece of writing, so that the reader never has to stop and recalibrate their sense of "when."
The core principle is simple: pick a time frame and stay in it unless you have a reason to leave. If you are narrating a past event, every verb in that narrative should be in past tense unless you are describing something that happened even earlier (past perfect: *had arrived*), something still ongoing (past progressive: *was running*), or genuinely stepping outside the narrative frame. The error most writers make is not a principled shift — it's accidental drift. A writer starts a story in past tense, gets absorbed in the action, and slides into present tense mid-paragraph because the historical present feels vivid in the moment. The result is a reader who stumbles: "Wait, are we in the past or the present now?"
Sequence of tenses is the more formal side of tense consistency, governing how tenses in dependent clauses align with the main clause. When the main (reporting) verb is in the past, the subordinate clause follows: "She said she *was* tired" (not "is"), "He claimed he *had* seen it" (not "has seen"). This is called backshifting — tenses in reported speech shift one step back in time relative to the main verb. The present *is* becomes past *was*; the present perfect *has seen* becomes past perfect *had seen*. When the main verb is in the present, no backshift occurs: "She says she *is* tired." The mistake is mixing these — using a present-tense reporting verb with backshifted subordinate clauses, or a past reporting verb with unshifted ones.
The practical test for any draft is to scan the verbs alone, in sequence, and ask: does this tell a coherent temporal story? If the tenses jump without cause — past to present to past — something needs repair. Not every shift is wrong: the historical present (narrating past events as if they're happening now: "Caesar crosses the Rubicon") is a legitimate stylistic choice, but once you choose it, consistency demands you maintain it throughout that passage. The revision strategy is to choose the appropriate frame, locate every verb in the problem section, and align each one to that frame — adjusting sequence-of-tenses constructions accordingly.