4. Earnings per Share

Basic earnings per common share amounts are calculated using the weighted average number of common shares outstanding for the period. Diluted earnings per common share amounts are calculated using the weighted average number of common shares outstanding plus the additional dilution for all potentially dilutive securities, such as nonvested restricted stock. During loss periods, diluted loss per share amounts are based on the weighted average number of common shares outstanding, because the inclusion of common stock equivalents would be antidilutive.

The dilutive effect of stock-based compensation arrangements is accounted for using the treasury stock method. The Company includes as assumed proceeds the amount of compensation cost attributed to future services and not yet recognized. For the thirteen weeks ended May 5, 2018 and April 29, 2017, there were 108,000 and 145,000 shares of nonvested restricted stock, respectively, excluded from the calculation of diluted earnings per share because of antidilution.

The following table provides a reconciliation of the average number of common shares outstanding used to calculate basic earnings per share to the number of common shares and common stock equivalents outstanding used in calculating diluted earnings per share for the thirteen week periods ended May 5, 2018 and April 29, 2017:


	Thirteen Weeks Ended
	May 5, 2018	April 29, 2017
Average number of common shares outstanding	13,578,100	14,719,130
Incremental shares from assumed vesting of nonvested restricted stock	53,166	60,800
Average number of common shares and common stock equivalents outstanding	13,631,266	14,779,930