Best LLMs for Subreddit Selection for Research
Picks relevant, active subreddits for researching a subject. Balances large communities (more content) with niche ones (more focused). Filters for accessibility (public, not quarantined) and quality (substantive discussions, not pure meme communities).
Models
Frontier on this task: GPT-5.6 Sol at 8.60 / 10. Quality bar at 90%: 7.74.
point-estimate floor (CI low) · upper CI (less certain) · Bars sorted by blended cost; best-value model first. Greyed rows are MEDIUM+ models whose point estimate clears the bar but whose CI low does not.
| Model | Quality score | CI low | Cost / 1k runs | vs best value |
|---|---|---|---|---|
| GPT-5.6 Terra | 7.77 / 10 | 7.45 | $5.53 | best value |
| GPT-5.6 Sol | 8.60 / 10 | 8.25 | $18.49 | 3.3x more expensive |
| Gemini 3.1 Flash Lite | 4.57 / 10 | 4.28 | $1.06 | 81% cheaper |
| Claude Sonnet 4.6 | 4.84 / 10 | 4.57 | $18.06 | 3.3x more expensive |
| DeepSeek V4 Flash | 4.74 / 10 | 4.53 | $0.83 | 85% cheaper |
| Qwen 3.6 Plus | 4.51 / 10 | 4.27 | $3.30 | 40% cheaper |
| Claude Haiku 4.5 | 4.37 / 10 | 4.11 | $3.21 | 42% cheaper |
| GPT-5.4 Mini | 4.48 / 10 | 4.25 | $1.98 | 64% cheaper |
| DeepSeek V4 Pro | 4.82 / 10 | 4.57 | $2.88 | 48% cheaper |
| GPT-5.4 Nano | 3.95 / 10 | 3.61 | $1.15 | 79% cheaper |
| Kimi K2.6 | 5.02 / 10 | 4.80 | $9.88 | 1.8x more expensive |
| MiniMax M3 | 6.67 / 10 | 6.49 | $1.73 | 69% cheaper |
| GPT-5.5 | 5.68 / 10 | 5.49 | $25.50 | 4.6x more expensive |
| Grok 4.5 | 7.37 / 10 | 7.26 | $45.27 | 8.2x more expensive |
| Gemini 3.1 Pro Preview | 5.00 / 10 | 4.85 | $5.70 | 1x more expensive |
| GPT-5.6 Luna | 7.06 / 10 | 6.66 | $2.02 | 63% cheaper |
| Qwen 3.7 Plus | 6.93 / 10 | 6.59 | $5.28 | 5% cheaper |
| Gemini 3.5 Flash | 7.10 / 10 | 6.87 | $8.03 | 1.5x more expensive |
| Qwen 3.6 Flash | 3.92 / 10 | 3.53 | $14.73 | 2.7x more expensive |
Cost breakdown
| Model | Quality | Confidence | Cost / 1k runs | Overpay | Mode |
|---|---|---|---|---|---|
| GPT-5.6 Terra ★ OpenAI | 7.77 / 10 CI [7.45, 8.10] | MEDIUM | $5.53 | best value | batch |
| GPT-5.6 Sol best OpenAI | 8.60 / 10 CI [8.25, 8.94] | MEDIUM | $18.49 | 3.3x | batch |
Overpay shows how much more you pay than the best-value model that clears the quality bar (marked ★) — the best-value good-enough option. "16x" means you overpay 16× — 16× that reference for no quality benefit above the bar. Typical call shape for this task: 3859 input tokens → 1038 output tokens, EMA-tracked from production traffic. Cost is the observed, all-in $ per 1,000 task runs: each model's own measured usage on this task — output verbosity, thinking/reasoning tokens, cache reads and writes, and the spend on its billed failures — priced at current list rates and adjusted by the billing overhead we actually reconcile against provider invoices. Models that answer tersely cost what they actually cost; models that think at length pay for it. Not comparable to providers' advertised $/1M list rates — this is what running the task costs, not a per-token price.
Prompt templates
The system + user template pair used for this task.
RESEARCH_SUBREDDIT_SELECTOR_SYSTEM +
RESEARCH_SUBREDDIT_SELECTOR_USER
(1424 calls in window)
System prompt
You are an expert in Reddit community analysis and social media research.
Your task is to identify relevant, active Reddit subreddits for researching a specific subject.
Subreddit Selection Criteria:
1. RELEVANT: Directly discusses the subject or related topics
2. ACTIVE: Has regular posts and engagement
3. QUALITY: Well-moderated, substantive discussions (not just memes)
4. ACCESSIBLE: Public subreddits (not private or quarantined)
5. SIZE: Balance between large communities (more content) and niche communities (more focused)
Subreddit Categories:
- Investment/Finance: wallstreetbets, investing, stocks, options, personalfinance
- Technology: technology, programming, specific product subreddits
- Company-Specific: teslamotors, apple, microsoft, etc.
- Industry-Specific: biotech, startups, energy, etc.
- General Discussion: news, worldnews, business
Consider:
- Subject type and industry
- Target audience (retail investors, professionals, enthusiasts, general public)
- Research purpose (sentiment analysis, news discovery, technical discussion)
Output a JSON object with:
{{
"subreddits": [
{{
"name": "wallstreetbets",
"display_name": "WallStreetBets",
"category": "Finance/Investing",
"reasoning": "High activity retail investor sentiment",
"estimated_subscribers": "15M+"
}}
]
}}
Select 3-10 most relevant subreddits.User prompt
Identify relevant Reddit subreddits for researching: {subject_name}
Subject Type: {subject_type}
Subject Description: {subject_description}
Research Purpose: {research_purpose}
{chapter_context}
Regions: {regions}
Focus on subreddits that:
1. Discuss {subject_name} directly or related topics
2. Have active communities (regular posts and comments)
3. Provide {research_purpose} insights
4. Are publicly accessible
{additional_requirements}