diff --git a/src/main/java/ru/ulstu/service/TimeSeriesService.java b/src/main/java/ru/ulstu/service/TimeSeriesService.java
index e9bf4b0..d7b4920 100644
--- a/src/main/java/ru/ulstu/service/TimeSeriesService.java
+++ b/src/main/java/ru/ulstu/service/TimeSeriesService.java
@@ -45,7 +45,11 @@ public class TimeSeriesService {
     }
 
     public List<TimeSeries> getGroupedTendencies(List<TimeSeries> timeSeriesList) {
-        return timeSeriesList.stream().map(this::getGroupedTendencies).collect(Collectors.toList());
+        return timeSeriesList
+                .stream()
+                .filter(ts -> ts.getValues() != null && ts.getLength() > 5)
+                .map(this::getGroupedTendencies)
+                .collect(Collectors.toList());
     }
 
     public TimeSeries getGroupedTendencies(TimeSeries timeSeries) {