Usage + Reliability

Tool Usage and Reliability Trends

Monthly and yearly breakdown of HRA tool page visits, plus cross-tool reliability trends. KG Explorer launched in Aug 2025 and immediately became the most-visited tool.

KG Explorer61,618
EUI14,504
RUI5,776
CDE5,537
FTU Explorer4,918

Monthly Visits per Tool

Nov 2023 – May 2026 · Use the slider or scroll to zoom

31 months
release
Workshop / Events
Published (right axis)
Preprint
Dashed lines = releases · Shaded areas = workshops / events
Click on the chart to see 47 HRA-related publications in this date range
HRA Release ImpactAvg visits (release month + 1 after) vs avg (2 months before)
v2.0Dec 2023
120+52%

6th release: 33 ASCT+B tables, 65 3D reference objects, systems graph added

v2.1Jun 2024
524+33%

7th release: 8 new OMAPs, ~100 new dataset-to-HRA mappings, terminology expansions

v2.2Dec 2024
529-75%

8th release: HRA Knowledge Graph covers all digital objects with provenance

v2.3Jun 2025
729-30%

9th release: 73 organs, HRApop v1.0, 662 datasets across 17 organs, 26 FTUs

v2.4Dec 2025
6,224+48%

10th release: 77 3D ref objects, 4,810 AS, 1,334 CT, 2,070 biomarkers, KG app + HRApop Visualizer launched

Publication ↔ Traffic Correlation47 papers across 34 months
3,248avg visits (pub months)
2,491avg visits (no pubs)
+30%publication lift

Months with publications see 30% more traffic on average. Correlation is suggestive but confounders (releases, workshops) often overlap with publication months.

Visits by Year (Grouped)

Year-over-year tool breakdown

All-Time Tool Share

Cumulative visits across all tools

When Each Tool Gets Used — By Hour (EST)

Event count per hour of day (EST) · KG Explorer peaks late morning EST; EUI follows a similar pattern

Hourly · All Tools
EUIpeaks at 2pm EST (3pm EDT)
RUIpeaks at 3pm EST (4pm EDT)
CDEpeaks at 2pm EST (3pm EDT)
FTU Explorerpeaks at 2pm EST (3pm EDT)
KG Explorerpeaks at 10am EST (11am EDT)

Visits by Day of Week

Stacked by tool · EUI Sunday spike driven by March 2024 workshop event skewing the aggregate

Day of Week
Weekend Drop-off

All tools see sharply lower weekend traffic — CDE, RUI, and FTU drop 60–80%. The pattern is most consistent with weekday professional or academic workflows, with lighter casual usage on weekends.

EUI Sunday Anomaly

EUI shows unusually high Sunday visits — an artifact of the March 2024 workshop (7,140 visits) whose dates happened to fall on a Sunday, skewing the DOW aggregate.

KG Explorer: Flat Across Week

KG Explorer has the most even distribution across days — reflecting its international user base across multiple time zones rather than a single institution's working hours.

Cross-Tool Reliability
Logged Errors43,75720.1% of all events
Clustered Samples50,130Rows used for root-cause clustering
Top Error Source21,760Portal/Other (49.7% of errors)
Peak→Latest Drop80.5%Oct 2025 → May 2026
All-Time Error Rate by Toolerrors per 100 tool visits (cumulative)
KG Explorer31.5%19,433 errors / 61,618 visitsHighest error rate
FTU Explorer14.8%728 errors / 4,918 visits
EUI11.5%1,670 errors / 14,504 visits
CDE2.1%119 errors / 5,537 visits
RUI0.8%47 errors / 5,776 visitsLowest error rate

Where Do the Errors Come From?

43,757 logged error events (20.1% of all events) · stack trace clustering (50,130 sampled) shows 72% traceable to 3 fixable bugs

Quality · All Tools

Error volume by source

Portal/Other (unattributed app context) and KG Explorer account for most error volume; RUI and CDE are low.

Errors by root cause

Top 2 causes alone account for 62% of all errors — both are infrastructure issues, not UX.Source: NLP clustering on 50,130 error messages — separate universe from the event-log error count above.

Fix #16,438 errors

API request blocked before response — the technology list request fails before any HTTP status comes back, so users see loading failures instead of a clear server message. Fix CORS policy and cross-origin routing on apps.humanatlas.io/api/v1.

Fix #26,712 errors

KG Explorer missing icons — SVG assets for organs and products (all-organs, kidneys, ftu, schema…) not resolving on CDN. Audit CDN asset paths.

Fix #32,251 errors

EUI selection state is sometimes empty — the 3D picker tries to read the first selected item even when nothing is selected, causing a client crash. Add a null/length guard in getLastPickedObject before indexing.

Root-Cause Composition by Source

Stacked error counts by source (Portal/Other + tools)

All Sources
Priority #126,498 errors (60.6%)

Repair icon asset delivery

Audit icon manifest paths, publish missing SVGs, and add pre-deploy link checks against CDN URLs.

Bucket: Icon retrieval failures

Priority #26,360 errors (14.5%)

Stabilize technology list API access

Fix CORS + gateway routing for /api/v1/technology-names and add retries with fallback cache.

Bucket: Net/CORS: technology list API

Priority #35,473 errors (12.5%)

Triage long-tail errors

Sample the uncategorized tail weekly and promote recurring patterns into explicit buckets.

Bucket: Other

Priority #42,251 errors (5.1%)

Guard empty selection states

Add null/length checks before index access in selection handlers (e.g., getLastPickedObject).

Bucket: Null selection read

Error Volume Over Time

Monthly error events by source (tools + Portal/Other) · Oct 2025 spike = KG launch + CDN icon failures · trend improving

Error Trend
Oct 2025 Spike

12,387 errors in October — driven by KG Explorer's August launch triggering CDN icon resolution failures that accumulated until CDN paths were corrected.

Declining Trend

Errors fell from 12,387 → 3,149 → 2,976 in Oct–Dec 2025. Jan 2026 is partial but tracking lower. The CDN fixes are taking hold.

Portal/Other Category

The large “Portal/Other” bar represents errors from the HRA portal layer before app-attribution is set in the event payload. Some KG icon failures were logged without app attribution, so they appear under Portal/Other.

Tool Error Rate Timeline
Peak Error Rate69.3Errors per 100 visits (Oct '25)
Current Error Rate69.3Errors per 100 visits (latest month)
Rate Improvement0%Reduction from launch to now
RUI Return Rate29.9%Users returning · EUI 17.3% · KG 22.5%

KG Explorer — Error Rate

Hover a month to see that month's top errors · click to pin

KG Explorer · Quality

May '26 — top error sources(2,108 errors)

hover to explore · click to pin
Icon failure: product:undefined545
Icon failure: organ:all-organs516
Http failure: cdn.humanatlas.io/hra-kg--staging//kg/digital-objects.jsonld: 404 Not Found332
Icon failure: product:landmark285
Icon failure: product:3d-organ270
Icon failure: organ:fallopian-tube160

Peaked at 69.3 in Oct '25 (CDN icon failures + CORS on the technology list API). Down to 69.3 — 0% improvement.

EUI — Error Rate

Hover a month to see that month's top errors · click to pin

EUI · Quality

Q2 '26 — top error sources(173 errors)

hover to explore · click to pin
Http failure: apps.humanatlas.io/api/v1/biomarker-term-occurences: 0 Unknown Error48
Http failure: apps.humanatlas.io/api/v1/cell-type-term-occurences: 0 Unknown Error38
Http failure: apps.humanatlas.io/api/v1/ontology-term-occurences: 0 Unknown Error37
Http failure: apps.humanatlas.io/api/v1/aggregate-results: 0 Unknown Error15
Http failure: apps.humanatlas.io/api/v1/technology-names: 0 Unknown Error12
Icon failure: product:eui9
Http failure: apps.humanatlas.io/api/v1/cell-type-term-occurences?ontology-terms=%5B%22htt4
Http failure: apps.humanatlas.io/api/v1/biomarker-term-occurences?ontology-terms=%5B%22htt4
Http failure: apps.humanatlas.io/api/v1/provider-names: 0 Unknown Error3
Http failure: apps.humanatlas.io/api/v1/consortium-names: 0 Unknown Error3

EUI peaked at 197.7 errors/100 visits (Nov 2025). API failures (session-token, ontology endpoints) and null-ref errors on map initialization are the top drivers.

CDE — Error Rate

Hover a month to see that month's top errors · click to pin

CDE · Quality

Q2 '26 — top error sources(51 errors)

hover to explore · click to pin
Http failure: cdn.humanatlas.io/ui/cde-ui/assets/data/gallery/studies.yaml: 0 Unknown Erro11
Icon failure: social:bluesky6
Icon failure: social:facebook6
Icon failure: social:youtube5
Icon failure: social:linkedin5
Icon failure: social:x5
Icon failure: social:instagram4
Icon failure: social:github4
Http failure: cdn.humanatlas.io/ui/cde-ui/assets/content/gallery/data.yaml: 0 Unknown Erro3
Study not found: histogram2

CDE peaked at 1228 errors/100 visits (Jan 2026), latest at 14.3 (May 2026). Angular DI errors (NG0201, NG0950) and undefined property reads dominate.

RUI — Error Rate

Hover a month to see that month's top errors · click to pin

RUI · Quality

Q2 '26 — top error sources(2 errors)

hover to explore · click to pin
Icon failure: product:rui2

RUI generally has low error rates — peak at 12.7 errors/100 (Dec 2025). Icon retrieval from localhost dev environments accounts for most of the noise.

FTU Explorer — Error Rate

Hover a month to see that month's top errors · click to pin

FTU Explorer · Quality

Q2 '26 — top error sources(234 errors)

hover to explore · click to pin
[ { "expected": "object", "code": "invalid_type", "path": [ "@graph", 63
60
Http failure: 127.0.0.1:5501/docs/iftu-testing/assets/ftu-cell-summaries.jsonld?id=https:/34
Http failure: cns-iu.github.io/docs/iftu-testing/assets/links.yml: 404 OK19
Http failure: cns-iu.github.io/docs/iftu-testing/assets/resources.yml: 404 OK19
[ { "expected": "object", "code": "invalid_type", "path": [], "message":13
Http failure: cns-iu.github.io/docs/iftu-testing/assets/ftu-cell-summaries.jsonld?id=https8
Http failure: localhost:5500/v1/ftu-illustrations?id=: 404 Not Found6
Http failure: localhost:3000/ftu-explorer/v1/ftu-illustrations?id=: 404 Not Found6
Http failure: apps.humanatlas.io/api/v1/ftu-illustrations: 0 Unknown Error6

FTU Explorer peaked at 810.1 errors/100 (Feb 2026). can't access property "clientWidth", this.viewportElement is undefined is the dominant error (564 hits). Localhost dev noise also inflates counts.

Are Users Coming Back? — Tool Return Rates

% of monthly active users who visited that tool in a prior month · data from H2 2025 onward

Retention
RUI Leads Retention

RUI has the highest return rate at 29.9% in the latest month. Tissue registration is a recurring professional task — users come back because they have to.

EUI Stabilizing

EUI sits at 17.3%, consistent with a mixed audience of returning researchers and first-time workshop visitors.

KG Explorer Building

KG Explorer launched at near-zero return rate and is now at 22.5%. Adding bookmarking and share features could accelerate habit formation significantly.

KG Explorer

Launched Aug 2025, reached 3,891 visits/mo by Oct 2025 — fastest-growing tool in the HRA suite.

EUI Spike

March 2024 saw 7,140 EUI visits (41× baseline), almost certainly a university workshop or class exercise.

Oct 2024 Event

CDE, EUI, and RUI all spiked simultaneously in Oct 2024 — likely a conference demonstration.

RUI Growth

RUI visits have gradually increased in 2025, possibly reflecting growing adoption in tissue registration workflows.