diff --git a/ProcessLib/Utils/ProcessUtils.cpp b/ProcessLib/Utils/ProcessUtils.cpp
index 8e7dfcf2804083af467786e46dce78a3b6288763..2274622185b9b768781e68326a57fc511544d377 100644
--- a/ProcessLib/Utils/ProcessUtils.cpp
+++ b/ProcessLib/Utils/ProcessUtils.cpp
@@ -70,7 +70,7 @@ std::vector<std::reference_wrapper<ProcessVariable>> findProcessVariables(
 
     auto var_names = pv_config.getConfigParameterList<std::string>(tag);
 
-    if (var_names.size() == 0)
+    if (var_names.empty())
         OGS_FATAL("Config tag <%s> is not found.", tag.c_str());
 
     // collect variable names to check if there are duplicates