diff --git a/processing/src/main/java/edu/harvard/hms/dbmi/avillach/hpds/processing/timeseries/ObservationDistanceProcessor.java b/processing/src/main/java/edu/harvard/hms/dbmi/avillach/hpds/processing/timeseries/ObservationDistanceProcessor.java
new file mode 100644
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--- /dev/null
+++ b/processing/src/main/java/edu/harvard/hms/dbmi/avillach/hpds/processing/timeseries/ObservationDistanceProcessor.java
@@ -0,0 +1,132 @@
+package edu.harvard.hms.dbmi.avillach.hpds.processing.timeseries;
+
+import edu.harvard.hms.dbmi.avillach.hpds.data.phenotype.ColumnMeta;
+import edu.harvard.hms.dbmi.avillach.hpds.data.phenotype.KeyAndValue;
+import edu.harvard.hms.dbmi.avillach.hpds.data.phenotype.PhenoCube;
+import edu.harvard.hms.dbmi.avillach.hpds.data.query.Query;
+import edu.harvard.hms.dbmi.avillach.hpds.processing.AbstractProcessor;
+import edu.harvard.hms.dbmi.avillach.hpds.processing.AsyncResult;
+import edu.harvard.hms.dbmi.avillach.hpds.processing.HpdsProcessor;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Component;
+
+import java.io.IOException;
+import java.io.Serializable;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.*;
+import java.util.function.Predicate;
+import java.util.stream.Collectors;
+
+@Component
+public class ObservationDistanceProcessor implements HpdsProcessor {
+
+    private static final Logger LOG = LoggerFactory.getLogger(ObservationDistanceProcessor.class);
+
+    private final AbstractProcessor abstractProcessor;
+
+    @Autowired
+    public ObservationDistanceProcessor(AbstractProcessor abstractProcessor) {
+        this.abstractProcessor = abstractProcessor;
+    }
+
+    @Override
+    public String[] getHeaderRow(Query query) {
+        return new String[]{"QUERIED_CONCEPT", "PATIENT_ID", "FIRST_OBSERVATION", "LAST_OBSERVATION"};
+    }
+
+    private static final class PatientJourney {
+        final long firstObs, lastObs;
+        final String path;
+        final int patient;
+
+        public PatientJourney(String path, int patient) {
+            this(Long.MAX_VALUE, Long.MIN_VALUE, path, patient);
+        }
+
+        public PatientJourney(long firstObs, long lastObs, String path, int patient) {
+            this.firstObs = firstObs;
+            this.lastObs = lastObs;
+            this.path = path;
+            this.patient = patient;
+        }
+
+        public PatientJourney from(long newFirst, long newLast) {
+            newFirst = Long.min(newFirst, firstObs);
+            newLast = Long.max(newLast, lastObs);
+            if (newFirst == firstObs && newLast == lastObs) {
+                return this;
+            }
+            return new PatientJourney(newFirst, newLast, path, patient);
+        }
+
+        public long distance() {
+            return lastObs - firstObs;
+        }
+    }
+
+    @Override
+    public void runQuery(Query query, AsyncResult asyncResult) {
+        Set<Integer> recordedJourneys = new HashSet<>();
+        for (String concept : query.getAnyRecordOf()) {
+            LOG.info("Creating user journeys for concept {}", concept);
+            Optional<PhenoCube<?>> maybeCube = abstractProcessor.nullableGetCube(concept);
+            if (maybeCube.isEmpty()) {
+                continue;
+            }
+            maybeCube.get().keyBasedIndex().stream()
+                .filter(Predicate.not(recordedJourneys::contains))
+                .map(id -> new PatientJourney(concept, id))
+                .map(this::updateJourney)
+                .sorted((a, b) -> -Long.compare(b.distance(), a.distance()))
+                .peek(j -> recordedJourneys.add(j.patient))
+                .limit(100)
+                .forEach(journey -> write(asyncResult.getTempFilePath(), journey));
+            LOG.info("Done creating user journeys for concept {} to {}", concept, asyncResult.getTempFilePath());
+        }
+    }
+
+    private void write(Path path, PatientJourney journey) {
+        try {
+            List<String> row = List.of(journey.path, journey.patient + "", journey.distance() + "");
+            Files.write(path, (String.join("\t", row) + "\n").getBytes());
+        } catch (IOException e) {
+            LOG.error("Failed to write", e);
+        }
+    }
+
+    private PatientJourney updateJourney(PatientJourney journey) {
+        LOG.info("Creating user journey for path {}", journey.path);
+        for (ColumnMeta value : abstractProcessor.getDictionary().values()) {
+            PatientJourney finalJourney = journey;
+            journey = abstractProcessor.nullableGetCube(value.getName())
+                .map(cube -> updateJourneyWithCube(finalJourney, cube))
+                .orElse(journey);
+        }
+        LOG.info("Done creating journey for path {}", journey.path);
+        return journey;
+    }
+
+    /**
+     * Update journey with new min / max timestamps from cube for this patient.
+     * If min / max values are unchanged, original journey object is returned.
+     */
+    private PatientJourney updateJourneyWithCube(PatientJourney journey, PhenoCube<?> cube) {
+        List<? extends KeyAndValue<?>> values = cube.getValuesForKeys(Set.of(journey.patient));
+        if (values == null) {
+            return journey;
+        }
+        long last = values.stream()
+            .mapToLong(KeyAndValue::getTimestamp)
+            .max()
+            .orElse(journey.lastObs);
+        long first = values.stream()
+            .mapToLong(KeyAndValue::getTimestamp)
+            .min()
+            .orElse(journey.firstObs);
+
+        return journey.from(first, last);
+    }
+}