{ "study": "Rychlost webu: mobil vs. pocitac", "publisher": "CIAD - Cesky institut pro AI a data", "url": "https://ciad.cz/studie/rychlost-webu-mobil-vs-pocitac/", "license": "CC BY 4.0", "generated": "2026-08-03", "scan_date": "2026-08-03", "note_on_data": "Agregatni data bez domenovych jmen a bez jmen firem. Vzorek je konvenicni (vyzkumny korpus CIAD pouzivany napric paralelnimi studiemi), ne nahodny nebo reprezentativni vzorek ceske ekonomiky. Mereno nastrojem Google PageSpeed Insights API v5, jeden zivy beh na domenu na strategii (mobil, pocitac), stejny den.", "sample": { "total_domains_targeted": 299, "mobile_unreachable_or_error": 46, "mobile_offsite_redirect_excluded": 25, "mobile_usable_denominator": 228, "desktop_unreachable_or_error": 47, "desktop_offsite_redirect_excluded": 24, "desktop_usable_denominator": 228, "sampling_method": "convenience sample: CIAD research corpus used across parallel studies, not random or representative of the Czech economy" }, "score_scale_note": "performance_score and accessibility_score fields are on a 0 to 1 scale, not 0 to 100. Confirmed by observed range (min 0.06, max 1.00 on mobile).", "lcp_threshold_note": "The 4000ms 'poor' threshold for LCP is Google's own published Core Web Vitals classification (good < 2500ms, needs improvement 2500-4000ms, poor > 4000ms), not a CIAD-defined threshold.", "mobile": { "denominator_reachability": 228, "error_breakdown": { "psi_bad_request": 44, "timeout": 2 }, "performance_score_0to1": { "n": 224, "min": 0.06, "median": 0.6, "p75": 0.68, "p90": 0.87, "max": 1.0, "mean": 0.6098 }, "perf_score_buckets": { "denominator": 224, "good_ge_0_90": { "n": 15, "pct": 6.7 }, "needs_improvement_0_50_to_0_89": { "n": 163, "pct": 72.8 }, "poor_lt_0_50": { "n": 46, "pct": 20.5 } }, "lcp_ms": { "n": 224, "min": 758, "median": 8723.28, "p75": 14524.02, "p90": 22441.13, "max": 97035.23, "mean": 11958.46 }, "lcp_over_4000ms": { "n": 224, "count": 194, "pct": 86.6 }, "lcp_4000ms_or_under": { "n": 224, "count": 30, "pct": 13.4 }, "lcp_distribution": { "denominator": 224, "unit": "ms", "buckets": [ { "label": "0-1s", "range_ms": [ 0, 1000 ], "count": 7, "pct": 3.1 }, { "label": "1-1.5s", "range_ms": [ 1000, 1500 ], "count": 1, "pct": 0.4 }, { "label": "1.5-2s", "range_ms": [ 1500, 2000 ], "count": 2, "pct": 0.9 }, { "label": "2-2.5s", "range_ms": [ 2000, 2500 ], "count": 2, "pct": 0.9 }, { "label": "2.5-3s", "range_ms": [ 2500, 3000 ], "count": 3, "pct": 1.3 }, { "label": "3-4s", "range_ms": [ 3000, 4000 ], "count": 15, "pct": 6.7 }, { "label": "4-6s", "range_ms": [ 4000, 6000 ], "count": 36, "pct": 16.1 }, { "label": "6-9s", "range_ms": [ 6000, 9000 ], "count": 49, "pct": 21.9 }, { "label": "9-14s", "range_ms": [ 9000, 14000 ], "count": 49, "pct": 21.9 }, { "label": "14-22s", "range_ms": [ 14000, 22000 ], "count": 37, "pct": 16.5 }, { "label": "22s+", "range_ms": [ 22000, null ], "count": 23, "pct": 10.3 } ] }, "tbt_ms": { "n": 224, "median": 150.5, "p75": 368.0, "p90": 740.5, "mean": 288.76 }, "cls": { "n": 228, "median": 0.0001, "p75": 0.0201, "p90": 0.1559, "mean": 0.0485 } }, "desktop": { "denominator_reachability": 228, "error_breakdown": { "psi_bad_request": 43, "timeout": 3, "psi_server_error": 1 }, "performance_score_0to1": { "n": 226, "min": 0.19, "median": 0.84, "p75": 0.94, "p90": 0.98, "max": 1.0, "mean": 0.8077 }, "perf_score_buckets": { "denominator": 226, "good_ge_0_90": { "n": 82, "pct": 36.3 }, "needs_improvement_0_50_to_0_89": { "n": 132, "pct": 58.4 }, "poor_lt_0_50": { "n": 12, "pct": 5.3 } }, "lcp_ms": { "n": 226, "min": 204, "median": 1561.07, "p75": 2419.55, "p90": 3633.69, "max": 9809.35, "mean": 2013.5 }, "lcp_over_4000ms": { "n": 226, "count": 16, "pct": 7.1 }, "lcp_4000ms_or_under": { "n": 226, "count": 210, "pct": 92.9 }, "lcp_distribution": { "denominator": 226, "unit": "ms", "buckets": [ { "label": "0-1s", "range_ms": [ 0, 1000 ], "count": 50, "pct": 22.1 }, { "label": "1-1.5s", "range_ms": [ 1000, 1500 ], "count": 53, "pct": 23.5 }, { "label": "1.5-2s", "range_ms": [ 1500, 2000 ], "count": 45, "pct": 19.9 }, { "label": "2-2.5s", "range_ms": [ 2000, 2500 ], "count": 23, "pct": 10.2 }, { "label": "2.5-3s", "range_ms": [ 2500, 3000 ], "count": 20, "pct": 8.8 }, { "label": "3-4s", "range_ms": [ 3000, 4000 ], "count": 19, "pct": 8.4 }, { "label": "4-6s", "range_ms": [ 4000, 6000 ], "count": 9, "pct": 4.0 }, { "label": "6-9s", "range_ms": [ 6000, 9000 ], "count": 4, "pct": 1.8 }, { "label": "9-14s", "range_ms": [ 9000, 14000 ], "count": 3, "pct": 1.3 }, { "label": "14-22s", "range_ms": [ 14000, 22000 ], "count": 0, "pct": 0.0 }, { "label": "22s+", "range_ms": [ 22000, null ], "count": 0, "pct": 0.0 } ] }, "tbt_ms": { "n": 226, "median": 105.0, "p75": 280.5, "p90": 467.0, "mean": 194.21 }, "cls": { "n": 228, "median": 0.0029, "p75": 0.0289, "p90": 0.1143, "mean": 0.0542 } }, "comparison": { "good_band_pct_point_gap": 29.6, "lcp_over_4000ms_pct_point_gap": 79.5, "median_lcp_ratio_mobile_to_desktop": 5.59 }, "scan_method": { "type": "active, single-page, non-authenticated", "description": "One Google PageSpeed Insights API v5 (Lighthouse) run per domain per strategy (mobile, desktop). No repeated runs, no averaging across multiple runs.", "measurement_window_utc": { "min": "2026-08-03T19:18:48Z", "max": "2026-08-03T19:44:02Z" } }, "lcp_distribution_note": "Buckets anchor on Google's own published Core Web Vitals LCP thresholds (2500ms = good, 4000ms = poor) as exact bucket edges, with finer buckets in each population's dense region (under 2500ms for desktop, 4000ms-22000ms for mobile). The top bucket (22000ms+) is open-ended so the single 97035ms mobile outlier does not define the axis. Counts sum exactly to the strategy's usable LCP denominator (mobile 224, desktop 226), matching lcp_ms.n above." }