diff --git a/ledger/predict.go b/ledger/predict.go
index 24de9cf..55d2238 100644
--- a/ledger/predict.go
+++ b/ledger/predict.go
@@ -9,7 +9,29 @@ import (
 )
 
 func RegisterWithContributionPrediction(reg Register, window time.Duration) (Register, error) {
-	return reg, io.EOF
+	result := make(Register)
+	result.PushAll(reg)
+	for _, name := range result.Names() {
+		subregister, err := registerWithContributionPredictionForName(result, window, name)
+		if err != nil {
+			return nil, err
+		}
+		result.PushAll(subregister)
+	}
+	return result, nil
+}
+
+func registerWithContributionPredictionForName(reg Register, window time.Duration, name string) (Register, error) {
+	return nil, io.EOF
+}
+
+func registerWithContributionPredictionForNameForCurrency(reg Register, window time.Duration, name string, currency Currency) (Register, error) {
+	return nil, io.EOF
+	// find median contribution value+frequency in most recent half
+	// find median contribution value+frequency in most recent quarter
+	// find median contribution value+frequency in most recent eighth
+	// weighted averages of medians
+	// project
 }
 
 func BPIsWithFixedGrowthPrediction(bpis BPIs, window time.Duration, pattern string, apy float64) (BPIs, error) {