Chapter 6

LingVarBench

A framework for generating high-quality, privacy-compliant synthetic healthcare transcripts using stochastic introspective optimization.

The Privacy Challenge

Medical NLP is hindered by the lack of publicly available data due to stringent privacy regulations (HIPAA). LingVarBench addresses this by generating synthetic patient-doctor conversations that are indistinguishable from real ones but contain zero real patient data.

Architecture

The system uses a two-stage process:

  1. Generation Pipeline: A DSPy module creates a conversation based on a medical topic, injecting specific entities (diseases, medications) while ensuring natural flow.
  2. SIMBA Optimizer: The Stochastic Introspective Mini-Batch Ascent optimizer evolves the prompt itself to maximize linguistic diversity and medical accuracy.

SIMBA Optimization

SIMBA treats the prompt as an organism in an evolutionary algorithm.

class SIMBAOptimizer:
    def optimize_prompt(self, base_prompt, evaluation_data):
        population = self._initialize_population(base_prompt)
        for generation in range(self.generations):
            # Evaluate -> Select -> Mutate -> Repeat
            fitness_scores = [self._evaluate(p) for p in population]
            population = self._create_next_generation(population, fitness_scores)
        return best_prompt

Real-World Impact

Models trained purely on LingVarBench synthetic data achieved >90% accuracy when tested on real, private healthcare datasets. This "synthetic-to-real" transfer learning proves that high-quality synthetic data can effectively substitute for sensitive real-world data.