# SEO Content Drift > Content and translation drift detection: find pages decaying over time, machine-translation quality drift on i18n sites, staleness signals, and prioritize what to refresh. Methodology, thresholds, a 0-100 freshness score, and refresh cadence tied to Next.js + next-intl + hreflang. Use when content is going stale, traffic is decaying on old pages, translations drifted from source, deciding what to refresh, or planning a content-decay audit. Triggers on: content drift, content decay, stale content, translation drift, machine translation quality, i18n parity drift, refresh priority, content freshness, content rot, decaying pages, next-intl drift, hreflang parity. - Skill: `pixartseu/seo-content-drift` (Agent Skill) - Install (CLI): `npx skillmds@latest add pixartseu/seo-content-drift` - Raw SKILL.md: https://api.skillmd.com/api/skills/pixartseu/seo-content-drift/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Marketing & Growth - Author: PIXARTSeu (https://skillmd.com/u/pixartseu) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/pixartseu/seo-content-drift --- # Content & Translation Drift Detect content that has decayed since publish, machine-translation that has drifted from its source, and turn the findings into a ranked refresh queue. Two failure modes, one discipline: 1. **Content decay** — a page that ranked and converted slowly loses relevance, traffic, and rank as the topic, competitors, or facts move on. The page didn't change; the world did. 2. **Translation drift** — localized variants fall out of sync with the source locale: stale facts, missing sections, untranslated fragments, or low machine-translation quality that tanks the localized variant while the source ranks fine. This is an **audit/analysis** skill. It gives you the methodology, thresholds, a 0-100 score, and a falsifiability check — not a vendor product. Use your own crawler, analytics export, and Search Console data; the techniques are tool-agnostic. Default stack: Next.js 15 (App Router, RSC) + next-intl, deployed on Coolify. Where freshness must surface in markup we generate it from `next/metadata` so it stays in sync with routing. --- ## Part 1 — Baseline, then diff against time Drift is only measurable against a known-good snapshot. Capture a baseline per URL+locale, then re-measure on a cadence and diff. Persist snapshots (SQLite, JSON in the repo, or a CMS field) keyed on a **normalized URL** (lowercase host, strip default ports, sort query params, drop UTM, strip trailing slash) plus the locale. Capture per snapshot: | Field | Why it matters | |-------|----------------| | `title`, `meta_description` | CTR signal; drift here moves clicks before rank | | `h1`, `h2[]` | Topic + section structure | | `word_count`, `body_text_hash` (SHA-256) | Detects silent content edits / shrinkage | | `published_at`, `modified_at` | Age and last-touch — the core staleness inputs | | `internal_links_out`, `internal_links_in` | Decay correlates with losing internal links | | `outbound_links_alive` | Dead external links are a decay smell | | Search Console: clicks, impressions, avg position (28-day) | The ground truth for decay | | `schema[]` / schema hash | Stale `datePublished`/`dateModified`, removed types | For i18n sites, snapshot **every locale of the same logical page**, not just the source. Drift is a per-locale property. --- ## Part 2 — Content decay signals & thresholds No single metric proves decay. Score the evidence; a page is "decaying" when multiple signals agree. Thresholds below are starting points — calibrate to the site's own seasonality. | Signal | Threshold (decaying) | Leading vs lagging | |--------|----------------------|--------------------| | Clicks trend (last 90d vs prior 90d) | Down ≥ 25% | Lagging | | Impressions trend (90d vs prior) | Down ≥ 20% | **Leading** — impressions fall before clicks | | Avg position trend | Worse by ≥ 3 positions | Leading | | Content age since `modified_at` | > 365 days for YMYL/fast-moving; > 540d otherwise | Leading | | Internal links in | Dropped vs baseline | Leading | | Dead outbound links | ≥ 1 | Leading | | SERP recency mismatch | Top-3 competitors updated < 90d ago, you > 365d | Leading | | Body word count vs baseline | Shrank ≥ 15% (silent gutting) | Leading | Key insight: **impressions and position regress before clicks do.** Watch impressions as the early-warning indicator; by the time clicks crater you've already lost the quarter. ### Freshness score (0-100) Compute per URL+locale. Higher = healthier. Drives the refresh queue. ``` freshness = 100 − min(40, clicks_drop_pct * 0.8) # traffic loss, capped 40 − min(20, impressions_drop_pct * 0.6) # demand loss, capped 20 − min(15, max(0, position_delta) * 3) # rank slip, 3 pts per position, capped 15 − age_penalty(modified_at) # 0 / 5 / 12 / 20 by age bucket − min(10, dead_outbound_links * 5) # capped 10 − (10 if body_shrank_15pct else 0) + min(10, internal_links_in_gained * 2) # recovery credit, capped 10 ``` `age_penalty`: 0 (<180d), 5 (180-365d), 12 (365-540d), 20 (>540d) for fast-moving topics; halve the buckets for evergreen reference content. Bands: **80-100 healthy**, **60-79 watch**, **40-59 refresh soon**, **<40 refresh now / consider consolidate-or-prune**. ### Refresh prioritization Don't refresh by score alone — refresh by **opportunity = traffic potential × fixability**. ``` priority = (impressions_90d / 1000) * (1 - freshness/100) * position_leverage ``` `position_leverage` is highest where a small rank gain yields outsized clicks: ~2.0 for avg position 4-10 (page-1 striking distance), ~1.0 for 11-20, ~0.4 for 21+. A page sitting at position 6 with high impressions and a low freshness score is the textbook refresh win; a page at position 45 with 30 impressions is a prune candidate, not a refresh. Outcome buckets: - **Refresh** — high impressions, page-1-adjacent, decayed. Update facts, expand thin sections, re-earn internal links, bump `dateModified` only when content genuinely changed. - **Consolidate** — multiple thin pages competing for the same intent → merge + 301. - **Prune** — near-zero traffic, no internal links, no strategic value → 410/redirect. --- ## Part 3 — Translation / i18n drift On a next-intl site each locale is a separate page that can rot independently. Three drift types: ### 3a. Parity drift (source moved, locale didn't) The source locale was edited; the translation still reflects the old version. | Signal | Threshold | |--------|-----------| | Source `modified_at` newer than locale `modified_at` | > 30 days gap | | Source `word_count` vs locale (length-ratio adjusted) | Diverged ≥ 20% beyond expected expansion | | Section count: source `h2[]` count ≠ locale `h2[]` count | Any mismatch = missing/extra sections | | Source has schema/CTA the locale lacks | Any | Expected length expansion (used to normalize the word-count check): EN→DE ≈ +20-35%, EN→FR/ES/IT ≈ +15-25%, EN→FI ≈ −10 to +10%. A locale far below its expected ratio is likely truncated or partially untranslated; far above with no source change can signal MT padding. ### 3b. Untranslated fragments Detect source-language leakage inside a non-source locale: hardcoded English in a German page, a missing translation key falling back to source, mixed-script runs. Heuristics that work without a paid API: - Per-block language-detect; flag blocks whose detected language ≠ the page locale above a coverage threshold (e.g., > 10% of body blocks off-locale). - Scan rendered HTML for next-intl fallback markers / raw message keys (`messages.about.title`) that escaped to output — a sign of a missing key, not a translation. - Compare the set of message keys per locale JSON; missing keys = guaranteed fallback leakage. ### 3c. Machine-translation quality drift MT output that is grammatical but wrong, robotic, or off-brand drags the localized variant's engagement and rankings while the source is healthy. You can't fully grade MT mechanically, but these proxies catch the worst: | Proxy | Smell | |-------|-------| | Localized variant CTR ≪ source CTR at same position | Title/desc reads unnatural in-locale | | Localized variant bounce/dwell far worse than source | Body reads like a bad machine | | Repeated literal idioms / calques | Word-for-word MT, not localized | | Brand terms / product names translated when they shouldn't be | No glossary / do-not-translate list | | Number, date, currency, units not localized | MT translated text but not formats | For the qualitative read, sample affected blocks and have an LLM rate fluency/adequacy/terminology 1-5 against the source — but treat that as advisory, and confirm with a native reviewer before acting on B2B or YMYL content. The mechanical proxies above decide *which* pages get the human read. ### Cross-reference Parity and untranslated-fragment findings feed the `seo-hreflang` skill's content-parity check. If parity drift is severe, the hreflang set is technically valid but semantically lying about equivalence — fix the content, not the tags. --- ## Part 4 — Surfacing freshness in Next.js Where freshness should be a ranking/markup signal, emit it from metadata and schema so it tracks the actual content, never a hardcoded "updated today" lie. ```tsx // app/[locale]/blog/[slug]/page.tsx import type { Metadata } from "next"; export async function generateMetadata( { params }: { params: Promise<{ locale: string; slug: string }> } ): Promise { const { locale, slug } = await params; const post = await getPost(slug, locale); return { title: post.title, description: post.description, alternates: { // hreflang stays in sync with routing; only emit locales that actually exist languages: Object.fromEntries( post.availableLocales.map((l) => [l, `/${l}/blog/${slug}`]) ), }, openGraph: { type: "article", // Only set modifiedTime when content truly changed — never bump on a redeploy publishedTime: post.publishedAt, modifiedTime: post.modifiedAt, }, }; } ``` ```tsx // JSON-LD: dateModified must reflect real edits, not build time function ArticleJsonLd({ post }: { post: Post }) { const json = { "@context": "https://schema.org", "@type": "Article", headline: post.title, inLanguage: post.locale, datePublished: post.publishedAt, dateModified: post.modifiedAt, // sourced from CMS, not new Date() }; return (