It was not only Stalin's model. Soviet was actually directly transformed from an empire to a "communism" country, before 1917 they were an empire, since then they turned out to be socialist and communism, it was too fast, there was something backward left in Soviet's system. In China, it's different, but communism is still an dominated ideology, the communism evolved itself in China, to accommodate the new changes in our society, which means the policy has consistency and the progress we have made is effective.
Off-topic: Do your students learn Marxism-Leninism at school or college?