How do proportional, progressive and regressive taxes meet the criteria of simplicity and equity ?

What do economists mean when they use the latin expression ceteris paribus?

As a project manager for a large construction company, shaun decided to make the performance appraisal process as painless as possible for his crew. he spent a considerable amount of time creating performance standards he felt were reasonable, and after six months' time, he scheduled individual appointments with each worker to discuss strengths and weaknesses and areas that needed improvement according to the standards he privately set. some employees were sent to vestibule training, and one even got a promotion with additional compensation. what did he fail to do correctly

Wilson center is a private not-for-profit voluntary health and welfare entity. during 2017, it received unrestricted pledges of $638,000, 65 percent of which were payable in 2017, with the remainder payable in 2018 (for use in 2018). officials estimate that 14 percent of all pledges will be uncollectible. a. how much should wilson center report as contribution revenue for 2017? b. in addition, a local social worker, earning $20 per hour working for the state government, contributed 600 hours of time to wilson center at no charge. without these donated services, the organization would have hired an additional staff person. how should wilson center record the contributed service?