Batch 26 — Sentinel QA Notes

Verdict: NEEDS_FIXES Date reviewed: 2026-03-24 Reviewer: Sentinel (QA subagent)

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Files Reviewed

| File | Frontmatter | 1200+ words | Math/Stats | No stock picks | No guarantees | CTA correct | Readable | |------|-------------|-------------|------------|----------------|---------------|-------------|----------| | batch-26-how-to-invest-dividend-growth-stocks.md | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | | batch-26-hidden-cost-mutual-fund-fees.md | ✅ | ✅ | ❌ | ✅ | ✅ | ✅ | ✅ | | batch-26-how-to-build-emergency-fund.md | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | | batch-26-4-percent-rule-retirement-explained.md | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | | batch-26-how-to-invest-in-index-funds.md | ✅ | ✅ | ❌ | ✅ | ✅ | ✅ | ✅ |

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Issues Found

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Issue 1

File: batch-26-hidden-cost-mutual-fund-fees.md Severity: Math error Location: Section "The Math That Should Shock You"

Problem: Fund B (0.05% fee) final value is stated as $749,534 and the difference as $175,185.

Verified using FV = PV × (1 + net_rate)^n:

• PV = $100,000, gross = 7%, fee = 0.05%, net = 6.95%, n = 30
• Correct FV = $100,000 × (1.0695)^30 = $750,626
• Correct difference = $750,626 − $574,349 = $176,277

The article understates the low-fee outcome by $1,092 and the gap by $1,092.

Fix: Replace:

- **Fund B (expense ratio: 0.05%):** Net annual return = 6.95%
  - $100,000 × (1.0695)^30 = **$749,534**

**Difference: $175,185**

With:

- **Fund B (expense ratio: 0.05%):** Net annual return = 6.95%
  - $100,000 × (1.0695)^30 = **$750,626**

**Difference: $176,277**

Also update the description line in the intro ("$175,000 gap" → "$176,000 gap") and the final summary paragraph ("over $175,000" is still directionally acceptable but should be corrected to "over $176,000" for precision).

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Issue 2

File: batch-26-how-to-invest-in-index-funds.md Severity: Math error Location: Section "Why Low Cost Wins"

Problem: Investor B (0.05% fee) ending value is stated as $374,767 and the gap as ~$87,600.

Verified using FV = PV × (1 + net_rate)^n:

• PV = $50,000, gross = 7%, fee = 0.05%, net = 6.95%, n = 30
• Correct FV = $50,000 × (1.0695)^30 = $375,313
• Correct gap = $375,313 − $287,175 = $88,138

The article understates the low-fee outcome by $546 and the gap by $546 (exactly half the error in File 2, as expected from the halved starting balance).

Fix: Replace:

- **Investor B** pays a 0.05% expense ratio (typical of broad index ETFs): net return 6.95%, ending value ≈ **$374,767**

The fee difference of 0.95% produces nearly a **$87,600 gap**

With:

- **Investor B** pays a 0.05% expense ratio (typical of broad index ETFs): net return 6.95%, ending value ≈ **$375,313**

The fee difference of 0.95% produces nearly a **$88,100 gap**

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Passing Notes (no action needed)

• Trinity Study attribution (File 4): Correctly attributed to Cooley, Hubbard & Walz, 1998, Trinity University. 95% success rate on 50/50 portfolio over 30 years stated accurately.
• 4% rule math (File 4): $1M × 4% = $40,000; Year 2 at 3% inflation = $41,200. ✅
• Fund A math (Files 2 & 5): $574,349 and $287,175 are both correct. ✅
• SPIVA claim (File 2): "80%–90% underperform over 15-year horizons" is consistent with published SPIVA data. ✅
• Dividend Aristocrats (File 1): 25 consecutive years threshold is correct. ✅
• No specific stock picks in any file. ✅
• No guaranteed return language in any file. ✅
• All CTAs point to valueofstock.com. ✅
• Prose quality: All five articles are coherent, well-structured, and appropriate for a personal finance blog audience.