Shahlo plans corporate events for a consulting firm in Tashkent. On Monday her manager asked for the cost of a two-day workshop for the sales team. The answer was not in any single place.
The first email, from the venue, gave the room prices: 250 dollars a day for a standard room, and 400 dollars a day for the large hall, which is required for groups of more than 40 people. The second email, from the caterer, said that lunch and coffee cost 12 dollars per person per day. The third email, from the sales director, said only that "the whole team" would attend.
The number of people was in a table: the company's staff list, which showed 45 people in the sales team.
Shahlo put the sources together in order. Forty-five is more than forty, so the venue's rule sent the team to the large hall: two days at 400 dollars, or 800 dollars. The caterer's rule gave 45 people times 12 dollars times 2 days, or 1,080 dollars. The total came to 1,880 dollars.
Her colleague had estimated the same event the week before and arrived at 1,040 dollars. He had used the standard room, because he had not opened the venue's email, and he had counted lunch for one day only. Each source on its own was simple; the mistakes came from reading one source and guessing the rest.
Shahlo now keeps a one-line note for every source before she calculates anything: "venue — room rules", "caterer — price per person per day", "staff list — head count". Then she knows exactly where to look for each number.
The manager approved the budget the same afternoon and asked her to use the same method for the year-end party, which had five sources instead of three.