Link Building KPIs: Quality, Velocity, and Competitive Gap Analysis

Track referring domains by authority tier based on your industry baseline.

Tier 1: DR 70+ (high authority)
Tier 2: DR 40-69 (medium authority)
Tier 3: DR below 40 (low authority)

Target distribution: 10% Tier 1, 40% Tier 2, 50% Tier 3 for growth-stage programs, shifting to 20% Tier 1, 50% Tier 2, 30% Tier 3 as the program matures. If Tier 3 exceeds 70%, your outreach prioritizes volume over quality.

Use the Ahrefs API to pull authority scores:

def get_domain_rating(url, api_key):
    endpoint = "https://api.ahrefs.com/v3/domain-rating"
    params = {"target": url, "limit": 1}
    headers = {"Authorization": f"Bearer {api_key}"}
    response = requests.get(endpoint, headers=headers, params=params)
    return response.json().get('domain_rating', 0)

Compute semantic distance between the linking page's topic and your site's core topics using cosine similarity on TF-IDF vectors. A relevance score below 0.3 (on a 0-1 scale) provides minimal topical authority flow regardless of domain authority. Filter these links out of core link equity calculations.

Net New RDs = new_referring_domains - lost_referring_domains

A flat or declining net RD over 90 days indicates outreach fatigue or content asset decay. The 2025 Link Building Benchmarks report by Siege Media found that mature programs average 5-15 net new referring domains per month (Siege Media, 2025). Below 5 per month for two consecutive quarters signals that linkable assets need a refresh.

Break down acquisition velocity by asset type: guest posts, resource pages, digital PR, broken link replacements, and unlinked brand mentions.

Asset Efficiency = net_new_rds_from_asset_type / hours_invested_in_asset_type

Review asset efficiency quarterly and cull the lowest-performing type.

Backlink Gap = 1 - (your_unique_rds) / (total_unique_rds_of_competitors)

A gap above 70% means you are significantly under-linked. The gap should decrease by at least 5 percentage points per quarter. Priority targets are domains linking to multiple competitors but not to you. Ahrefs' Link Intersect tool surfaces these domains (Ahrefs, 2025).

Lost Link Rate = lost_links_this_month / total_links_last_month * 100

An annualized rate above 10% signals link decay from content rot or broken pages. Set up automated reclamation workflows when monthly rate exceeds 2%. Common causes: page moved without redirect, domain expired, or content was removed.