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103 lines
3.8 KiB
Markdown
103 lines
3.8 KiB
Markdown
# NLP Block Scoring
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## Purpose
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**NLP Block Scoring** is a mechanism used to select the most relevant response block based on:
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- Matching patterns between user input and block definitions
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- Configurable weights assigned to each entity type
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- Confidence values provided by the NLU engine for detected entities
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It enables more intelligent and context-aware block selection in conversational flows.
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## Core Use Cases
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### Standard Matching
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A user input contains entities that directly match a block’s patterns.
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```bash
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Example: Input: intent = enquiry & subject = claim
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Block A: Patterns: intent: enquiry & subject: claim
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Block A will be selected.
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```
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### High Confidence, Partial Match
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A block may match only some patterns but have high-confidence input on those matched ones, making it a better candidate than others with full matches but low-confidence entities.
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**Note: Confidence is multiplied by a pre-defined weight for each entity type.**
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```bash
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Example:
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Input: intent = issue (confidence: 0.92) & subject = claim (confidence: 0.65)
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Block A: Pattern: intent: issue
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Block B: Pattern: subject: claim
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➤ Block A gets a high score based on confidence × weight (assuming both weights are equal to 1).
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```
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### Multiple Blocks with Similar Patterns
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```bash
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Input: intent = issue & subject = insurance
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Block A: intent = enquiry & subject = insurance
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Block B: subject = insurance
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➤ Block B is selected — Block A mismatches on intent.
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```
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### Exclusion Due to Extra Patterns
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If a block contains patterns that require entities not present in the user input, the block is excluded from scoring altogether. No penalties are applied — the block simply isn't considered a valid candidate.
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```bash
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Input: intent = issue & subject = insurance
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Block A: intent = enquiry & subject = insurance & location = office
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Block B: subject = insurance & time = morning
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➤ Neither block is selected due to unmatched required patterns (`location`, `time`)
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```
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### Tie-Breaking with Penalty Factors
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When multiple blocks receive similar scores, penalty factors can help break the tie — especially in cases where patterns are less specific (e.g., using `Any` as a value).
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```bash
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Input: intent = enquiry & subject = insurance
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Block A: intent = enquiry & subject = Any
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Block B: intent = enquiry & subject = insurance
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Block C: subject = insurance
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Scoring Summary:
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- Block A matches both patterns, but subject = Any is considered less specific.
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- Block B has a redundant but fully specific match.
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- Block C matches only one pattern.
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➤ Block A and Block B have similar raw scores.
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➤ A penalty factor is applied to Block A due to its use of Any, reducing its final score.
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➤ Block B is selected.
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```
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## How Scoring Works
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### Matching and Confidence
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For each entity in the block's pattern:
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- If the entity `matches` an entity in the user input:
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- the score is increased by: `confidence × weight`
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- `Confidence` is a value between 0 and 1, returned by the NLU engine.
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- `Weight` is a configured importance factor for that specific entity type.
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- If the match is a wildcard (i.e., the block accepts any value):
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- A **penalty factor** is applied to slightly reduce its contribution:
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``confidence × weight × penaltyFactor``. This encourages more specific matches when available.
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### Scoring Formula Summary
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For each matched entity:
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```bash
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score += confidence × weight × [optional penalty factor if wildcard]
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```
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The total block score is the sum of all matched patterns in that block.
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### Penalty Factor
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The **penalty factor** is a global multiplier (typically less than `1`, e.g., `0.8`) applied when the match type is less specific — such as wildcard or loose entity type matches. It allows the system to:
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- Break ties in favor of more precise blocks
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- Discourage overly generic blocks from being selected when better matches are available
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