Stalin's goals were to regain power in the world and regain lost lands that were taken by the germans. By industrialization he had help Russia gained it, the growth and advancement. By which makes him successful for which he did not state the actions he would take to achieve it, making the 20 million deaths he caused not a stand that should be used against him.

Its a difference between Long term effects or Short term effects.

In short term, stalin had taken many lives but for the rest of the Russian population he gave them better standing in the world by forcing industrialization to occur. For change to occur something outside the "comfort zone" had to be done.

Although Stalin was a ruthless man, whose mismanagement led to twenty million Russians dying in battle and even more dying from his Five-Year-Plans, while he did whatever necessary to keep himself in power, Russia helped save Europe from the horrors of Hitler.