> ## Documentation Index > Fetch the complete documentation index at: https://docs.vortexiq.ai/llms.txt > Use this file to discover all available pages before exploring further. # Responsiveness Over Time, Website Performance (PageSpeed + CrUX) > Responsiveness Over Time for Website Performance (PageSpeed + CrUX) stores. Tracked live in Vortex IQ Nerve Centre. How to read it, why it matters, and how... **Metrics type:** [Supporting Metrics](/nerve-centre/overview#metrics-types-explained) • **Category:** [Website Performance](/nerve-centre/connectors#connectors-by-type) ## At a glance > **Interaction to Next Paint p75 over time**, daily time-series of mobile INP from CrUX. Pairs with [`crux_inp_p75`](/nerve-centre/kpi-cards/website-performance/click-responsiveness) snapshot for trend analysis. **The most JS-driven of the CWV trends**: INP regressions usually trace to specific JavaScript changes (new third-party tag, framework upgrade, widget refactor) rather than gradual content drift. **Critical caveat**: INP definition changed in March 2024 (replaced FID); year-over-year comparisons across that boundary are not apples-to-apples. | | | | ------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | **What it counts** | Time-series of `interaction_to_next_paint` p75 across the rolling 28-day CrUX window. Each daily data point reflects the trailing 28 days of real-user interaction measurements. | | **Sample type** | **Field data** sourced from CrUX. No direct lab-data trend equivalent (lab approximates via [`psi_lab_tbt`](/nerve-centre/kpi-cards/website-performance/page-freeze-time)). | | **The March 2024 boundary** | Pre-March 2024 trend data is FID, not INP. Comparing across the boundary requires acknowledging the methodology change: FID measured first-input delay only, INP measures all interactions. **Most sites saw INP "regression" of 100-300ms vs equivalent FID** simply because the metric definition changed; this isn't a real regression. | | **Common INP drift patterns** | (1) **Step regression on framework upgrades**: React 17→18, jQuery version bumps, BC theme updates can introduce new INP hotspots. (2) **Step regression on third-party additions**: a new chat widget, A/B testing tool, or analytics library that adds main-thread JS. (3) **Slow drift from accumulated tags**: GTM bloat over months. (4) **Cyclical**: peak shopping periods often show INP degradation as servers slow + more users on slower devices arrive. | | **Reading the trend** | Same pattern as LCP trend: direction (up = bad), slope, inflection points, threshold crossings (200ms = good/needs-improvement boundary). | | **The 28-day rolling smoothing** | Same smoothing as LCP: real-world step regressions appear as gradual rises in the trend over 28 days. | | **Why INP regressions often appear weeks after the actual change** | Users have to encounter the slow interaction first. New filter widget added today; users need 28 days of real-world filtering on it before the metric stabilises. | | **Sample size threshold** | CrUX requires sufficient real-user volume (\~1,000+ sessions per 28 days). | | **Currency** | n/a, time-series of milliseconds. | | **Time window** | `28D rolling × T` | | **Alert trigger** | `current value > 200ms` OR `7-day rolling delta > +50ms` (regression). | | **Sentiment key** | `psi_inp` | | **Roles** | owner, marketing, operations | ## Calculation Calculated automatically from your Website Performance (PageSpeed + CrUX) data. See the At a glance summary above for what the metric tracks and the worked example below for a typical reading. ## Worked example A US-based BigCommerce home goods store, mobile INP trend over 6 months ending Wednesday 15 May 26. | Month | INP p75 | Δ vs prior | Notes | | ---------------------------- | --------: | -----------------------: | ---------------------------------------------------- | | Nov 25 | 240ms | (baseline, post-MPP era) | Just over good threshold | | Dec 25 | 260ms | +20ms | Minor drift | | Jan 26 | 320ms | +60ms | Klaviyo SDK update added behavior tracking | | Feb 26 | 380ms | +60ms | Tidio chat widget version bump (heavier mount logic) | | Mar 26 | 460ms | +80ms | New filter widget on collection pages | | Apr 26 | 500ms | +40ms | Hotjar session recording added | | **May 26** | **520ms** | **+20ms** | **Current state, "poor" band** | | **Cumulative drift Nov→May** | | **+280ms (+117%)** | **6-month silent regression** | What the trend is telling us: 1. **INP doubled over 6 months.** Each individual change felt acceptable in isolation; cumulatively the site is now in the poor band, paying CWV ranking penalty. **Same pattern as LCP drift** but driven by JS changes rather than content/image changes. 2. **Five distinct contributing events identifiable from inflection points**: * Jan 26 Klaviyo SDK update (+60ms): vendor-side update added behavior tracking event listeners * Feb 26 Tidio version bump (+60ms): heavier chat widget mount logic * Mar 26 filter widget refactor (+80ms): in-house JS rewrite that introduced new long tasks * Apr 26 Hotjar addition (+40ms): session recording adds main-thread overhead * May 26 stabilisation (+20ms): typical month-over-month variance 3. **Vendor-side updates are the trickiest contribution** because the merchant didn't make a code change. Klaviyo and Tidio pushed new versions; the merchant inherited the regression. **Defence**: pin third-party script versions where vendors permit; otherwise monitor for vendor-update regressions specifically. 4. **The filter widget refactor in Mar 26** is the only first-party-controlled change and the largest single contribution (+80ms). **Refactor opportunity**: the new widget added long tasks that didn't exist before; a yield-to-main-thread pattern would have prevented the regression. 5. **Recovery path**: (a) **defer non-critical third-party scripts** (Tidio, Hotjar) to post-load, saves 200-300ms; (b) **refactor filter widget** with debouncing + virtualisation, saves 100-200ms; (c) **audit Klaviyo SDK** for unused event listeners, saves 50-100ms. **Total recovery: 350-600ms**, dropping INP from 520ms toward 200ms target. 6. **Watch for INP regressions specifically when**: (a) deploying framework or theme version bumps; (b) adding new third-party scripts; (c) refactoring interactive widgets (filters, sort, modals); (d) changing main-thread-heavy code paths. INP regressions are JS-driven and trace cleanly to JS changes. The diagnostic flow: 1. **Identify whether trend shows drift or step regression.** Step = single event; drift = cumulative. 2. **Cross-reference inflection points with deploy log + third-party-vendor announcements.** 3. **Profile current worst-INP interactions** (covered in [`psi_worst_inp_urls`](/nerve-centre/kpi-cards/website-performance/worst-inp-urls)) to validate where time is spent. 4. **Apply yield-to-main-thread + deferral patterns** to recover. Rapid-response playbook: | Time horizon | Action | | ------------- | --------------------------------------------------------------- | | First 1 hour | Identify inflection events; map to deploy log + vendor updates. | | First 7 days | Defer non-critical third-party JS. | | First 14 days | Refactor heaviest interactive widgets. | | Day 28 | Trend reflects fixes as 28-day rolling window absorbs. | ## Sibling cards merchants should reference together | Card | Why merchants reach for it | | ---------------------------------------------------------------------------------------------------- | ------------------------------------------------- | | [`crux_inp_p75`](/nerve-centre/kpi-cards/website-performance/click-responsiveness) | Static snapshot. | | [`crux_lcp_trend`](/nerve-centre/kpi-cards/website-performance/load-speed-over-time) | Sister CWV trend. | | [`crux_cls_trend`](/nerve-centre/kpi-cards/website-performance/layout-stability-over-time) | Sister CWV trend. | | [`crux_pass_rate_trend`](/nerve-centre/kpi-cards/website-performance/speed-test-pass-rate-over-time) | All-three pass rate trend. | | [`psi_score_trend`](/nerve-centre/kpi-cards/website-performance/performance-score-over-time) | Lab score trend; correlated. | | [`crux_regression_timeline`](/nerve-centre/kpi-cards/website-performance/crux-regression-timeline) | Composite regression detection. | | [`psi_worst_inp_urls`](/nerve-centre/kpi-cards/website-performance/worst-inp-urls) | Per-URL INP ranking. | | [`psi_third_party_cost`](/nerve-centre/kpi-cards/website-performance/third-party-cost) | Third-party drift commonly drives INP regression. | | [`psi_unused_js`](/nerve-centre/kpi-cards/website-performance/unused-javascript) | Unused JS contributes to INP. | ## Reconciling against the vendor's own dashboard **Where to look:** * **GSC → Core Web Vitals trend**, surfaces 90-day INP trend (post-March 2024). * **CrUX BigQuery dataset**, historical INP data; FID prior to March 2024. * **Web Vitals Chrome extension**, live INP measurement during page interaction. **Why the Vortex IQ INP trend may differ from external trend views:** | Reason | Direction | What to do | | ------------------------------------------------------ | --------------------------- | -------------------------------------------------- | | **Pre-March 2024 data is FID, not INP.** | Different metric basis | Anchor comparisons within the post-March-2024 era. | | **Window timing.** | Vortex IQ **lags** 1-2 days | Wait for refresh. | | **Smoothing.** Each daily point is 28-day rolling p75. | Smoothed | Real regressions appear as gradual rises. | **Cross-connector reconciliation:** primarily internal (with [`crux_inp_p75`](/nerve-centre/kpi-cards/website-performance/click-responsiveness), [`psi_lab_tbt`](/nerve-centre/kpi-cards/website-performance/page-freeze-time)). **Quick rule for support tickets:** if a merchant says *"INP regressed without me changing anything"*, the most common cause is third-party vendor updates pushing heavier scripts. Check Klaviyo, Tidio, Hotjar, and similar vendor changelogs for the date matching the inflection. ## Known limitations / merchant FAQs **My INP "regressed" 200ms in March 2024 but I didn't change anything. What happened?** Google replaced FID with INP as the official Core Web Vital in March 2024. Pre-March 2024 data was FID; post-March 2024 is INP. **The two metrics are different by design**: FID measured the first interaction's delay; INP measures the longest. Most sites saw a 100-300ms "regression" simply from the metric definition change. **My INP keeps drifting up despite my best efforts. Why?** Third-party vendor updates often. Klaviyo, Tidio, Optimizely, Hotjar, GTM tags push new versions that ship heavier JS. The merchant inherits the regression without making a code change. **Defence**: monitor the trend; when an inflection happens, check vendor changelogs for the matching date. **Why is INP harder to recover from than LCP?** LCP fixes are mostly mechanical (image format, preload). INP fixes require code changes (refactor heavy widgets, defer scripts, yield to main thread). **A 6-week INP recovery cycle is typical**; LCP recovery often completes in 2-3 weeks. **Should I pin third-party script versions?** Where vendors permit, yes. Pinning prevents inherited regressions. **However**: pinning means missing security patches and bug fixes. **Best practice**: pin major versions; allow patch versions; review monthly for upgrades. **Can Vortex IQ alert me on INP drift before it crosses the threshold?** Yes; alert at `7-day rolling delta > +50ms` catches drift early. Earlier signal than waiting for the absolute threshold breach. **How long does INP recovery take to reflect?** 28 days for full reflection. Same as LCP, the rolling window is identical. *** ### Tracked live in Vortex IQ Nerve Centre *Responsiveness Over Time* is one of hundreds of KPI pulses Vortex IQ tracks across Website Performance (PageSpeed + CrUX) and 70+ other ecommerce connectors. Nerve Centre runs the detection layer; Vortex Mind investigates the cause when something moves; Ask Viq lets you interrogate any number in plain English. [Start for free](https://app.vortexiq.ai/login) or [book a demo](https://www.vortexiq.ai/contact-us) to see this metric running on your own data.