diff --git a/analyzer/analyzer_main.cpp b/analyzer/analyzer_main.cpp
index 05d9f42..5df6295 100644
--- a/analyzer/analyzer_main.cpp
+++ b/analyzer/analyzer_main.cpp
@@ -1,21 +1,13 @@
 #include <assert.h>
-#include <libpdbg.h>
 #include <unistd.h>
 
 #include <analyzer/ras-data/ras-data-parser.hpp>
 #include <analyzer/service_data.hpp>
 #include <attn/attn_dump.hpp>
 #include <hei_main.hpp>
-#include <phosphor-logging/log.hpp>
 #include <util/pdbg.hpp>
 #include <util/trace.hpp>
 
-#include <algorithm>
-#include <fstream>
-#include <iostream>
-#include <map>
-#include <string>
-
 namespace analyzer
 {
 
@@ -30,6 +22,15 @@
 void initializeIsolator(std::vector<libhei::Chip>& o_chips);
 
 /**
+ * @brief  Will get the list of active chip and initialize the isolator.
+ * @param  i_isoData   The data gathered during isolation (for FFDC).
+ * @param  o_rootCause The returned root cause signature.
+ * @return True, if root cause has been found. False, otherwise.
+ */
+bool filterRootCause(const libhei::IsolationData& i_isoData,
+                     libhei::Signature& o_rootCause);
+
+/**
  * @brief Will create and submit a PEL using the given data.
  * @param i_isoData   The data gathered during isolation (for FFDC).
  * @param i_servData  Data regarding service actions gathered during analysis.
@@ -69,59 +70,6 @@
 
 //------------------------------------------------------------------------------
 
-bool __filterRootCause(const libhei::IsolationData& i_isoData,
-                       libhei::Signature& o_signature)
-{
-    // We'll need to make a copy of the list so that the original list is
-    // maintained for the log.
-    std::vector<libhei::Signature> sigList{i_isoData.getSignatureList()};
-
-    // For debug, trace out the original list of signatures before filtering.
-    for (const auto& sig : sigList)
-    {
-        trace::inf("Signature: %s 0x%0" PRIx32 " %s",
-                   util::pdbg::getPath(sig.getChip()), sig.toUint32(),
-                   __attn(sig.getAttnType()));
-    }
-
-    // Special and host attentions are not supported by this user application.
-    auto newEndItr =
-        std::remove_if(sigList.begin(), sigList.end(), [&](const auto& t) {
-            return (libhei::ATTN_TYPE_SP_ATTN == t.getAttnType() ||
-                    libhei::ATTN_TYPE_HOST_ATTN == t.getAttnType());
-        });
-
-    // Shrink the vector, if needed.
-    sigList.resize(std::distance(sigList.begin(), newEndItr));
-
-    // START WORKAROUND
-    // TODO: Filtering should be determined by the RAS Data Files provided by
-    //       the host firmware via the PNOR (similar to the Chip Data Files).
-    //       Until that support is available, use a rudimentary filter that
-    //       first looks for any recoverable attention, then any unit checkstop,
-    //       and then any system checkstop. This is built on the premise that
-    //       recoverable errors could be the root cause of an system checkstop
-    //       attentions. Fortunately, we just need to sort the list by the
-    //       greater attention type value.
-    std::sort(sigList.begin(), sigList.end(),
-              [&](const auto& a, const auto& b) {
-                  return a.getAttnType() > b.getAttnType();
-              });
-    // END WORKAROUND
-
-    // Check if a root cause attention was found.
-    if (!sigList.empty())
-    {
-        // The entry at the front of the list will be the root cause.
-        o_signature = sigList.front();
-        return true;
-    }
-
-    return false; // default, no active attentions found.
-}
-
-//------------------------------------------------------------------------------
-
 bool analyzeHardware(attn::DumpParameters& o_dumpParameters)
 {
     bool attnFound = false;
@@ -144,9 +92,17 @@
     libhei::IsolationData isoData{};
     libhei::isolate(chips, isoData);
 
+    // For debug, trace out the original list of signatures before filtering.
+    for (const auto& sig : isoData.getSignatureList())
+    {
+        trace::inf("Signature: %s 0x%0" PRIx32 " %s",
+                   util::pdbg::getPath(sig.getChip()), sig.toUint32(),
+                   __attn(sig.getAttnType()));
+    }
+
     // Filter for root cause attention.
     libhei::Signature rootCause{};
-    attnFound = __filterRootCause(isoData, rootCause);
+    attnFound = filterRootCause(isoData, rootCause);
 
     if (!attnFound)
     {
diff --git a/analyzer/filter-root-cause.cpp b/analyzer/filter-root-cause.cpp
new file mode 100644
index 0000000..421c674
--- /dev/null
+++ b/analyzer/filter-root-cause.cpp
@@ -0,0 +1,54 @@
+#include <assert.h>
+
+#include <hei_main.hpp>
+
+#include <algorithm>
+#include <limits>
+#include <string>
+
+namespace analyzer
+{
+
+//------------------------------------------------------------------------------
+
+bool filterRootCause(const libhei::IsolationData& i_isoData,
+                     libhei::Signature& o_rootCause)
+{
+    // We'll need to make a copy of the list so that the original list is
+    // maintained for the log.
+    std::vector<libhei::Signature> list{i_isoData.getSignatureList()};
+
+    // START WORKAROUND
+    // TODO: Filtering should be data driven. Until that support is available,
+    //       use the following isolation rules.
+
+    // Special and host attentions are not supported by this user application.
+    auto itr = std::remove_if(list.begin(), list.end(), [&](const auto& t) {
+        return (libhei::ATTN_TYPE_SP_ATTN == t.getAttnType() ||
+                libhei::ATTN_TYPE_HOST_ATTN == t.getAttnType());
+    });
+    list.resize(std::distance(list.begin(), itr));
+
+    // TODO: This is a rudimentary filter that first looks for any recoverable
+    //       attention, then any unit checkstop, and then any system checkstop.
+    //       This is built on the premise that recoverable errors could be the
+    //       root cause of an system checkstop attentions. Fortunately, we
+    //       just need to sort the list by the greater attention type value.
+    std::sort(list.begin(), list.end(), [&](const auto& a, const auto& b) {
+        return a.getAttnType() > b.getAttnType();
+    });
+    if (!list.empty())
+    {
+        // The entry at the front of the list will be the root cause.
+        o_rootCause = list.front();
+        return true;
+    }
+
+    // END WORKAROUND
+
+    return false; // default, no active attentions found.
+}
+
+//------------------------------------------------------------------------------
+
+} // namespace analyzer
diff --git a/analyzer/meson.build b/analyzer/meson.build
index 18fb57c..9324392 100644
--- a/analyzer/meson.build
+++ b/analyzer/meson.build
@@ -2,6 +2,7 @@
 analyzer_src = files(
     'analyzer_main.cpp',
     'create_pel.cpp',
+    'filter-root-cause.cpp',
     'guard.cpp',
     'hei_user_interface.cpp',
     'initialize_isolator.cpp',