estimating-work

估算开发任务所需的工作量。适用于规划冲刺周期、制定路线图，或规划项目时间表时使用。涵盖故事点、相对估算，以及对不确定性的考量。

SKILL.md

--- frontmatter

name: estimating-work
description: Estimate effort for development tasks. Use when planning sprints, roadmaps, or project timelines. Covers story points, relative estimation, and uncertainty.
allowed-tools: Read, Glob, Grep

Estimating Work

Estimation Approaches

Story Points

Relative complexity, not time.

Points	Complexity
1	Trivial, well understood
2	Simple, minor unknowns
3	Moderate complexity
5	Complex, some unknowns
8	Very complex, significant unknowns
13	Extremely complex, many unknowns
21+	Too big, needs decomposition

T-Shirt Sizing

For high-level estimates.

Size	Relative Effort
XS	Hours
S	1-2 days
M	3-5 days
L	1-2 weeks
XL	2-4 weeks

Estimation Factors

Consider:

•Complexity: How difficult is the problem?
•Uncertainty: How much is unknown?
•Effort: How much work is involved?
•Risk: What could go wrong?

Estimation Techniques

Planning Poker

•Present the task
•Everyone selects estimate privately
•Reveal simultaneously
•Discuss outliers
•Re-estimate if needed

Three-Point Estimation

code

Expected = (Optimistic + 4×Likely + Pessimistic) / 6

Reference Stories

Keep calibration stories:

•"This 3-point story took 2 days"
•"This 8-point story took a week"

Common Pitfalls

•Anchoring: First estimate biases others
•Optimism: Underestimating unknowns
•Scope Creep: Original estimate doesn't match final scope
•Ignoring Overhead: Code review, testing, deployment

Tips

•Estimate in ranges, not points
•Include buffer for unknowns
•Track actual vs. estimated
•Re-estimate when scope changes
•Don't estimate in hours (use relative sizing)