Estimate the probability of each mutually-exclusive category outcome using norovirus seasonality (summer lows) and WastewaterSCAN historical patterns, then blend the category probabilities via weighted average to identify the most likely resolution.
## Cross-Market Signals ### No signal found
1. [sq1 | web_search | STRONG cred 85 | UP | DATED] Norovirus cases are usually highest November to April, with fall and summer wastewater levels lowest, per WastewaterSCAN and peer-reviewed studies. 2. [sq1 | web_search | MODERATE cred 80 | UP | DATED] Combined WWTP data showed lowest norovirus RNA in fall and low levels in summer (PLOS Water, 2024). 3. [sq2 | web_search | STRONG cred 88 | NEUTRAL | RECENT] As of May 2026 national norovirus was in the MEDIUM category with a downward trend over the prior 21 days. 4. [sq2 | web_search | MODERATE cred 85 | DOWN | RECENT] Median norovirus concentration in May 2026 was down ~31% compared to April 2026, indicating continued seasonal decline. 5. [sq2 | web_search | STRONG cred 85 | DOWN | RECENT] Category trajectory was HIGH Nov 2025-March 2026, dropping to MEDIUM by May 2026, showing steady decline toward summer. 6. [sq3 | web_search | MODERATE cred 82 | DOWN | RECENT] Norovirus RNA detected in 99% of samples in May 2026, indicating persistent detection unlikely to reach Not Detected by August. 7. [sq3 | web_search | MODERATE cred 70 | UP | RECENT] Norovirus concentrations were elevated across all regions relative to typical summer-fall baseline as of the 2025-26 season. ## Cross-Market Signals ### No signal found Information gaps: - No WastewaterSCAN data beyond May 30, 2026 (June/July trajectory unknown) - No historical August-specific category readings from prior years for base rate - No detail on exact numeric thresholds separating Low/Medium/High tertiles - Unclear whether elevated 2025-26 season persists into summer Key uncertainties: - Whether medium-to-low decline continues at seasonal pace through August - Possibility of atypically high off-season baseline this year - Whether summer levels drop enough to reach Low vs. remain Medium - Potential category redefinition affecting resolution mapping
You are an elite superforecaster. Estimate the probability of each option for this Metaculus multiple-choice question.
## Question
What will be the nationwide wastewater detection category of Norovirus on August 1, 2026?
## Description / Resolution Criteria
## Description
NBC News: [Vomiting virus is spreading across most of the U.S.](https://www.nbcnews.com/health/health-news/norovirus-gastrointestinal-symptoms-spreading-us-wastewater-rcna347108)
`{"format": "bot_tournament_question", "info": {"hash_id": "dc217d022169948c", "sheet_id": "81"}}`
## Resolution Criteria
This question resolves as the national WastewaterSCAN wastewater category of norovirus at the [WastewaterSCAN Dashboard](https://data.wastewaterscan.org/) when checked by Metaculus on or after August 1, 2026.
## Fine Print
If the category is Not Detected or Not Calculated (or functional equivalent), the question resolves as Other. In case of accessibility issues with the main resolution source, Metaculus may check the July [monthly update](https://wwscan.ghost.io/) as a backup source. In case of changes to categorization, the question may resolve based on which third the new category falls into. For example, a new category of Very Low would be in the lower third and would be encompassed by the current Low category.
## Options
- High
- Medium
- Low
- Other
## Sub-question decomposition (planner)
- (w=0.50) Will norovirus wastewater levels in early August 2026 fall in the lowest third (Low category) as is typical for summer seasonality? — Norovirus is strongly seasonal, peaking in winter and reaching seasonal lows in summer; August 1 is deep in the off-seas
- (w=0.30) Will norovirus wastewater levels in early August 2026 be in the Medium category (middle third)? — Even in summer there can be residual or moderate detection, and unusual off-season activity could push into the middle t
- (w=0.20) Will norovirus wastewater levels in early August 2026 be in the High category (upper third) or resolve Other (Not Detected/Not Calculated)? — High is very unlikely in summer; Other is possible if detection falls below thresholds — both tail outcomes must be asse
## Synthesized evidence
1. [sq1 | web_search | STRONG cred 85 | UP | DATED] Norovirus cases are usually highest November to April, with fall and summer wastewater levels lowest, per WastewaterSCAN and peer-reviewed studies.
2. [sq1 | web_search | MODERATE cred 80 | UP | DATED] Combined WWTP data showed lowest norovirus RNA in fall and low levels in summer (PLOS Water, 2024).
3. [sq2 | web_search | STRONG cred 88 | NEUTRAL | RECENT] As of May 2026 national norovirus was in the MEDIUM category with a downward trend over the prior 21 days.
4. [sq2 | web_search | MODERATE cred 85 | DOWN | RECENT] Median norovirus concentration in May 2026 was down ~31% compared to April 2026, indicating continued seasonal decline.
5. [sq2 | web_search | STRONG cred 85 | DOWN | RECENT] Category trajectory was HIGH Nov 2025-March 2026, dropping to MEDIUM by May 2026, showing steady decline toward summer.
6. [sq3 | web_search | MODERATE cred 82 | DOWN | RECENT] Norovirus RNA detected in 99% of samples in May 2026, indicating persistent detection unlikely to reach Not Detected by August.
7. [sq3 | web_search | MODERATE cred 70 | UP | RECENT] Norovirus concentrations were elevated across all regions relative to typical summer-fall baseline as of the 2025-26 season.
## Cross-Market Signals
### No signal found
Information gaps:
- No WastewaterSCAN data beyond May 30, 2026 (June/July trajectory unknown)
- No historical August-specific category readings from prior years for base rate
- No detail on exact numeric thresholds separating Low/Medium/High tertiles
- Unclear whether elevated 2025-26 season persists into summer
Key uncertainties:
- Whether medium-to-low decline continues at seasonal pace through August
- Possibility of atypically high off-season baseline this year
- Whether summer levels drop enough to reach Low vs. remain Medium
- Potential category redefinition affecting resolution mapping
## Required pre-forecast walkthrough
Before giving probabilities, address these explicitly in your rationale:
(a) The time left until the question resolves.
(b) The status quo outcome — the option most likely if nothing changes from today.
(c) An outcome that would be SURPRISING but plausible.
## Calibration guidance
- **Status quo anchoring.** Good forecasters put extra weight on the status quo option because the world changes slowly most of the time.
- **Leave moderate probability on most options.** Good forecasters don't drop options to ~0% — leave ≥3-5% on every option to account for unexpected outcomes, unless you have strong specific evidence ruling them out.
- Avoid uniform-distribution laziness — most options are not equally likely.
- **Anchor on prediction markets.** If liquid market prices (Polymarket / Kalshi) for these options appear in the evidence, treat them as a strong prior and stay close to them absent specific contrary evidence.
## Output
Return ONLY valid JSON, no markdown fences:
{
"rationale": "<address (a) (b) (c) above, then explain your distribution — 4-7 sentences total>",
"probabilities": {
"High": <prob>,
"Medium": <prob>,
"Low": <prob>,
"Other": <prob>
}
}
Probabilities MUST sum to ~1.0 (renormalization is applied; close enough is fine).
{
"forecast": {
"evidence_brief": "1. [sq1 | web_search | STRONG cred 85 | UP | DATED] Norovirus cases are usually highest November to April, with fall and summer wastewater levels lowest, per WastewaterSCAN and peer-reviewed studies.\n2. [sq1 | web_search | MODERATE cred 80 | UP | DATED] Combined WWTP data showed lowest norovirus RNA in fall and low levels in summer (PLOS Water, 2024).\n3. [sq2 | web_search | STRONG cred 88 | NEUTRAL | RECENT] As of May 2026 national norovirus was in the MEDIUM category with a downward trend over the prior 21 days.\n4. [sq2 | web_search | MODERATE cred 85 | DOWN | RECENT] Median norovirus concentration in May 2026 was down ~31% compared to April 2026, indicating continued seasonal decline.\n5. [sq2 | web_search | STRONG cred 85 | DOWN | RECENT] Category trajectory was HIGH Nov 2025-March 2026, dropping to MEDIUM by May 2026, showing steady decline toward summer.\n6. [sq3 | web_search | MODERATE cred 82 | DOWN | RECENT] Norovirus RNA detected in 99% of samples in May 2026, indicating persistent detection unlikely to reach Not Detected by August.\n7. [sq3 | web_search | MODERATE cred 70 | UP | RECENT] Norovirus concentrations were elevated across all regions relative to typical summer-fall baseline as of the 2025-26 season.\n\n## Cross-Market Signals\n\n### No signal found\n\nInformation gaps:\n - No WastewaterSCAN data beyond May 30, 2026 (June/July trajectory unknown)\n - No historical August-specific category readings from prior years for base rate\n - No detail on exact numeric thresholds separating Low/Medium/High tertiles\n - Unclear whether elevated 2025-26 season persists into summer\n\nKey uncertainties:\n - Whether medium-to-low decline continues at seasonal pace through August\n - Possibility of atypically high off-season baseline this year\n - Whether summer levels drop enough to reach Low vs. remain Medium\n - Potential category redefinition affecting resolution mapping",
"forecast_prompt": "You are an elite superforecaster. Estimate the probability of each option for this Metaculus multiple-choice question.\n\n## Question\nWhat will be the nationwide wastewater detection category of Norovirus on August 1, 2026?\n\n## Description / Resolution Criteria\n## Description\nNBC News: [Vomiting virus is spreading across most of the U.S.](https://www.nbcnews.com/health/health-news/norovirus-gastrointestinal-symptoms-spreading-us-wastewater-rcna347108)\n\n`{\"format\": \"bot_tournament_question\", \"info\": {\"hash_id\": \"dc217d022169948c\", \"sheet_id\": \"81\"}}`\n\n## Resolution Criteria\nThis question resolves as the national WastewaterSCAN wastewater category of norovirus at the [WastewaterSCAN Dashboard](https://data.wastewaterscan.org/) when checked by Metaculus on or after August 1, 2026.\n\n## Fine Print\nIf the category is Not Detected or Not Calculated (or functional equivalent), the question resolves as Other. In case of accessibility issues with the main resolution source, Metaculus may check the July [monthly update](https://wwscan.ghost.io/) as a backup source. In case of changes to categorization, the question may resolve based on which third the new category falls into. For example, a new category of Very Low would be in the lower third and would be encompassed by the current Low category.\n\n## Options\n - High\n - Medium\n - Low\n - Other\n\n## Sub-question decomposition (planner)\n- (w=0.50) Will norovirus wastewater levels in early August 2026 fall in the lowest third (Low category) as is typical for summer seasonality? \u2014 Norovirus is strongly seasonal, peaking in winter and reaching seasonal lows in summer; August 1 is deep in the off-seas\n- (w=0.30) Will norovirus wastewater levels in early August 2026 be in the Medium category (middle third)? \u2014 Even in summer there can be residual or moderate detection, and unusual off-season activity could push into the middle t\n- (w=0.20) Will norovirus wastewater levels in early August 2026 be in the High category (upper third) or resolve Other (Not Detected/Not Calculated)? \u2014 High is very unlikely in summer; Other is possible if detection falls below thresholds \u2014 both tail outcomes must be asse\n\n## Synthesized evidence\n1. [sq1 | web_search | STRONG cred 85 | UP | DATED] Norovirus cases are usually highest November to April, with fall and summer wastewater levels lowest, per WastewaterSCAN and peer-reviewed studies.\n2. [sq1 | web_search | MODERATE cred 80 | UP | DATED] Combined WWTP data showed lowest norovirus RNA in fall and low levels in summer (PLOS Water, 2024).\n3. [sq2 | web_search | STRONG cred 88 | NEUTRAL | RECENT] As of May 2026 national norovirus was in the MEDIUM category with a downward trend over the prior 21 days.\n4. [sq2 | web_search | MODERATE cred 85 | DOWN | RECENT] Median norovirus concentration in May 2026 was down ~31% compared to April 2026, indicating continued seasonal decline.\n5. [sq2 | web_search | STRONG cred 85 | DOWN | RECENT] Category trajectory was HIGH Nov 2025-March 2026, dropping to MEDIUM by May 2026, showing steady decline toward summer.\n6. [sq3 | web_search | MODERATE cred 82 | DOWN | RECENT] Norovirus RNA detected in 99% of samples in May 2026, indicating persistent detection unlikely to reach Not Detected by August.\n7. [sq3 | web_search | MODERATE cred 70 | UP | RECENT] Norovirus concentrations were elevated across all regions relative to typical summer-fall baseline as of the 2025-26 season.\n\n## Cross-Market Signals\n\n### No signal found\n\nInformation gaps:\n - No WastewaterSCAN data beyond May 30, 2026 (June/July trajectory unknown)\n - No historical August-specific category readings from prior years for base rate\n - No detail on exact numeric thresholds separating Low/Medium/High tertiles\n - Unclear whether elevated 2025-26 season persists into summer\n\nKey uncertainties:\n - Whether medium-to-low decline continues at seasonal pace through August\n - Possibility of atypically high off-season baseline this year\n - Whether summer levels drop enough to reach Low vs. remain Medium\n - Potential category redefinition affecting resolution mapping\n\n## Required pre-forecast walkthrough\n\nBefore giving probabilities, address these explicitly in your rationale:\n (a) The time left until the question resolves.\n (b) The status quo outcome \u2014 the option most likely if nothing changes from today.\n (c) An outcome that would be SURPRISING but plausible.\n\n## Calibration guidance\n\n- **Status quo anchoring.** Good forecasters put extra weight on the status quo option because the world changes slowly most of the time.\n- **Leave moderate probability on most options.** Good forecasters don\u0027t drop options to ~0% \u2014 leave \u22653-5% on every option to account for unexpected outcomes, unless you have strong specific evidence ruling them out.\n- Avoid uniform-distribution laziness \u2014 most options are not equally likely.\n- **Anchor on prediction markets.** If liquid market prices (Polymarket / Kalshi) for these options appear in the evidence, treat them as a strong prior and stay close to them absent specific contrary evidence.\n\n## Output\n\nReturn ONLY valid JSON, no markdown fences:\n\n{\n \"rationale\": \"\u003caddress (a) (b) (c) above, then explain your distribution \u2014 4-7 sentences total\u003e\",\n \"probabilities\": {\n \"High\": \u003cprob\u003e,\n \"Medium\": \u003cprob\u003e,\n \"Low\": \u003cprob\u003e,\n \"Other\": \u003cprob\u003e\n }\n}\n\nProbabilities MUST sum to ~1.0 (renormalization is applied; close enough is fine).\n",
"models": [
"opus"
],
"probabilities": {
"High": 0.04,
"Low": 0.63,
"Medium": 0.28,
"Other": 0.05
},
"rationale": "(a) About two months of data are missing (June/July 2026), giving time for continued seasonal decline before the August 1 resolution. (b) Status quo: norovirus was MEDIUM and declining in May 2026 (down ~31% from April), and norovirus is strongly seasonal with summer being its low point\u2014so the natural trajectory points toward LOW by August. (c) A surprising but plausible outcome would be norovirus remaining MEDIUM due to an atypically elevated off-season baseline noted in the 2025-26 season, or dropping to Other/Not Detected. Given strong summer seasonality and the ongoing decline, LOW is the most likely category by August 1. MEDIUM retains meaningful weight because the decline may not fully complete and this season ran high. HIGH is very implausible in deep summer, and Other is unlikely given norovirus was detected in 99% of samples in May.",
"top_option": "Low"
},
"plan": {
"combination_logic": "weighted_average",
"domain": "health",
"n_sub_qs": 3,
"n_tools": 2,
"reasoning_approach": "Estimate the probability of each mutually-exclusive category outcome using norovirus seasonality (summer lows) and WastewaterSCAN historical patterns, then blend the category probabilities via weighted average to identify the most likely resolution.",
"sub_questions": [
{
"id": "sq1",
"question": "Will norovirus wastewater levels in early August 2026 fall in the lowest third (Low category) as is typical for summer seasonality?",
"rationale": "Norovirus is strongly seasonal, peaking in winter and reaching seasonal lows in summer; August 1 is deep in the off-season, making Low the strong base-case category.",
"weight": 0.5
},
{
"id": "sq2",
"question": "Will norovirus wastewater levels in early August 2026 be in the Medium category (middle third)?",
"rationale": "Even in summer there can be residual or moderate detection, and unusual off-season activity could push into the middle third.",
"weight": 0.3
},
{
"id": "sq3",
"question": "Will norovirus wastewater levels in early August 2026 be in the High category (upper third) or resolve Other (Not Detected/Not Calculated)?",
"rationale": "High is very unlikely in summer; Other is possible if detection falls below thresholds \u2014 both tail outcomes must be assessed.",
"weight": 0.2
}
],
"tool_requests": [
{
"parameters": {
"brief": "Find the current WastewaterSCAN national norovirus wastewater detection category and historical seasonal pattern, especially what category norovirus falls into during summer months (July-August) versus winter peaks. Look at data.wastewaterscan.org and wwscan.ghost.io monthly updates.",
"max_searches": 4,
"question_title": "What will be the nationwide wastewater detection category of Norovirus on August 1, 2026?"
},
"target_sub_questions": [
"sq1",
"sq2",
"sq3"
],
"tool_name": "claude_news"
},
{
"parameters": {
"queries": [
"WastewaterSCAN norovirus national category current level",
"norovirus wastewater summer August levels seasonality",
"WastewaterSCAN dashboard norovirus low medium high"
]
},
"target_sub_questions": [
"sq1",
"sq2",
"sq3"
],
"tool_name": "web_search"
}
]
},
"question": {
"close_time": "2026-07-06T00:00:00Z",
"description": "## Description\nNBC News: [Vomiting virus is spreading across most of the U.S.](https://www.nbcnews.com/health/health-news/norovirus-gastrointestinal-symptoms-spreading-us-wastewater-rcna347108)\n\n`{\"format\": \"bot_tournament_question\", \"info\": {\"hash_id\": \"dc217d022169948c\", \"sheet_id\": \"81\"}}`\n\n## Resolution Criteria\nThis question resolves as the national WastewaterSCAN wastewater category of norovirus at the [WastewaterSCAN Dashboard](https://data.wastewaterscan.org/) when checked by Metaculus on or after August 1, 2026.\n\n## Fine Print\nIf the category is Not Detected or Not Calculated (or functional equivalent), the question resolves as Other. In case of accessibility issues with the main resolution source, Metaculus may check the July [monthly update](https://wwscan.ghost.io/) as a backup source. In case of changes to categorization, the question may resolve based on which third the new category falls into. For example, a new category of Very Low would be in the lower third and would be encompassed by the current Low category.",
"options": [
"High",
"Medium",
"Low",
"Other"
],
"question_type": "multiple_choice",
"title": "What will be the nationwide wastewater detection category of Norovirus on August 1, 2026?"
},
"research": {
"cross_market_brief": "## Cross-Market Signals\n\n### No signal found",
"errors": [],
"has_cross_market": true,
"n_errors": 0,
"n_tools": 2,
"tools": [
{
"elapsed_s": 28.93,
"error": null,
"success": true,
"summary": "12 citations",
"tool_name": "claude_news"
},
{
"elapsed_s": 50.41,
"error": null,
"success": true,
"summary": "0 results",
"tool_name": "web_search"
}
]
},
"synthesis": {
"evidence": [
{
"claim": "Norovirus cases are usually highest November to April, with fall and summer wastewater levels lowest, per WastewaterSCAN and peer-reviewed studies.",
"credibility": 85,
"direction": "UP",
"priced_in": true,
"recency": "DATED",
"source": "web_search",
"strength": "STRONG",
"sub_question_id": "sq1"
},
{
"claim": "Combined WWTP data showed lowest norovirus RNA in fall and low levels in summer (PLOS Water, 2024).",
"credibility": 80,
"direction": "UP",
"priced_in": true,
"recency": "DATED",
"source": "web_search",
"strength": "MODERATE",
"sub_question_id": "sq1"
},
{
"claim": "As of May 2026 national norovirus was in the MEDIUM category with a downward trend over the prior 21 days.",
"credibility": 88,
"direction": "NEUTRAL",
"priced_in": true,
"recency": "RECENT",
"source": "web_search",
"strength": "STRONG",
"sub_question_id": "sq2"
},
{
"claim": "Median norovirus concentration in May 2026 was down ~31% compared to April 2026, indicating continued seasonal decline.",
"credibility": 85,
"direction": "DOWN",
"priced_in": true,
"recency": "RECENT",
"source": "web_search",
"strength": "MODERATE",
"sub_question_id": "sq2"
},
{
"claim": "Category trajectory was HIGH Nov 2025-March 2026, dropping to MEDIUM by May 2026, showing steady decline toward summer.",
"credibility": 85,
"direction": "DOWN",
"priced_in": true,
"recency": "RECENT",
"source": "web_search",
"strength": "STRONG",
"sub_question_id": "sq2"
},
{
"claim": "Norovirus RNA detected in 99% of samples in May 2026, indicating persistent detection unlikely to reach Not Detected by August.",
"credibility": 82,
"direction": "DOWN",
"priced_in": true,
"recency": "RECENT",
"source": "web_search",
"strength": "MODERATE",
"sub_question_id": "sq3"
},
{
"claim": "Norovirus concentrations were elevated across all regions relative to typical summer-fall baseline as of the 2025-26 season.",
"credibility": 70,
"direction": "UP",
"priced_in": true,
"recency": "RECENT",
"source": "web_search",
"strength": "MODERATE",
"sub_question_id": "sq3"
}
],
"information_gaps": [
"No WastewaterSCAN data beyond May 30, 2026 (June/July trajectory unknown)",
"No historical August-specific category readings from prior years for base rate",
"No detail on exact numeric thresholds separating Low/Medium/High tertiles",
"Unclear whether elevated 2025-26 season persists into summer"
],
"key_uncertainties": [
"Whether medium-to-low decline continues at seasonal pace through August",
"Possibility of atypically high off-season baseline this year",
"Whether summer levels drop enough to reach Low vs. remain Medium",
"Potential category redefinition affecting resolution mapping"
],
"n_evidence": 7
},
"timings": {
"forecast": 11.73,
"plan": 11.03,
"research": 50.41,
"synthesis": 13.79
}
}