diff --git a/Parameters.hpp b/Parameters.hpp
index 3e0b42f..65bd563 100644
--- a/Parameters.hpp
+++ b/Parameters.hpp
@@ -10,8 +10,7 @@ class Parameters
 public:
 	Parameters():
 		workerCount_(std::thread::hardware_concurrency()),
-		testDataLength_(4),
-		searchPattern_("ABC")
+		searchPattern_("")
 	{};
 
 	~Parameters() {};
@@ -25,10 +24,6 @@ public:
 			{
 				workerCount_ = std::stoi(arg.substr(2));
 			}
-			else if (0 == arg.compare(0, 2, "-l"))
-			{
-				testDataLength_ = std::stoi(arg.substr(2));
-			}
 			else if (0 == arg.compare(0, 1, "-"))
 			{
 				// invalid option
@@ -51,17 +46,14 @@ public:
 			<< "Usage: " << cmd << " [options] [search_pattern]" << std::endl
 			<< "Options" << std::endl
 			<< "  -wX   Number of parallel workers" << std::endl
-			<< "  -lY   Length of test-data string" << std::endl
 			<< std::endl;
 	};
 
 	unsigned WorkerCount() const { return workerCount_; };
-	unsigned TestDataLength() const { return testDataLength_; };
 	std::string SearchPattern() const { return searchPattern_; };
 
 private:
 	unsigned workerCount_;
-	unsigned testDataLength_;
 	std::string searchPattern_;
 };
 
diff --git a/main.cpp b/main.cpp
index ee273eb..dfa95d6 100644
--- a/main.cpp
+++ b/main.cpp
@@ -4,7 +4,6 @@
 #include <algorithm>
 #include <random>
 
-
 #include "ParallelSearch.hpp"
 #include "TestRunner.hpp"
 #include "Parameters.hpp"
@@ -24,7 +23,9 @@ void create_testdata(WordList& words)
 		for (str[1] = start; str[1] <= end; str[1]++)
 			for (str[2] = start; str[2] <= end; str[2]++)
 				for (str[3] = start; str[3] <= end; str[3]++)
+				{
 					words.push_back(std::string(str, 4));
+				}
 
 }
 
@@ -39,6 +40,29 @@ void run_wordsearch(ParallelWordSearch& search)
 	search.run();
 }
 
+void check_result(const WordList& haystack, const std::string& pattern, const ParallelWordSearch::ResultList& result)
+{
+	// check number of matches
+	const unsigned TESTPATTERN_LENGTH = 4;
+	unsigned expected_count = static_cast<unsigned>(pow(26.0, double(TESTPATTERN_LENGTH - pattern.size())));
+	std::cout << "Number of matches expected: " << expected_count << " got: " << result.size() << " --> " << ((result.size() == expected_count) ? "OK" : "ERROR") << std::endl;
+
+	// verify matches contain the search-pattern
+	unsigned valid_count = 0;
+	for (WordList::const_iterator itr : result)
+	{
+		if (itr->substr(0, pattern.size()) == pattern)
+		{
+			valid_count++;
+		}
+		else
+		{
+			std::cout << "Found mismatch: " << *itr << std::endl;
+		}
+	}
+
+	std::cout << "Verified " << valid_count << " matches --> " << ((result.size() == valid_count) ? "OK" : "ERROR") << std::endl;
+}
 
 int main(int argc, char** argv)
 {
@@ -55,7 +79,6 @@ int main(int argc, char** argv)
 	}
 
 	std::cout << "Workercount:     " << parameters.WorkerCount() << std::endl;
-	std::cout << "Testdata length: " << parameters.TestDataLength() << std::endl;
 	std::cout << "Search pattern:  " << parameters.SearchPattern() << std::endl;
 	std::cout << std::endl;
 
@@ -74,8 +97,13 @@ int main(int argc, char** argv)
 	time_span = TestRunner(run_wordsearch, parallelWordSearch);
 	std::cout << "parallel search found " << parallelWordSearch.get_result().size() << " matches:  " << time_span << " seconds" << std::endl;
 	
-	// TODO add validation of results
-	// TODO brush up output
+	std::cout << std::endl;
+	std::cout << "checking result of parallel search ..." << std::endl;
+
+	check_result(test_data, parameters.SearchPattern(), parallelWordSearch.get_result());
+
+	std::cout << std::endl;
+	std::cout << "Done." << std::endl;
 
 	std::cout << std::endl;