1. 螺旋模型：
螺旋模型是一种软件开发生命周期模型，高度用于风险驱动模型。基于给定项目的风险模式，螺旋模型帮助开发人员提高模型的效率，因为大多数风险已经处理。它由许多形成螺旋形状的循环组成，其中每个循环称为软件开发周期的阶段。
2.增量模型：
增量模型是一种软件开发模型，在该模型中，产品以增量方式进行分析、设计、实施和测试，直到产品完成。发生多个开发周期，这些周期被划分为更小的模块。通常，增量模型中的工作软件是在第一个模块期间生成的。该模块的每个后续版本都会在先前版本的基础上增加函数。在增量模型中，过程一直持续到实现完整的系统。
螺旋模型和增量模型的区别：
| S.No. | Spiral Model | Incremental Model |
|---|---|---|
| 1. | Spiral model is a software development model and is made with features of incremental, waterfall or evolutionary prototyping models. | Incremental Model is a software development model where the product is, analyzed, designed, implemented and tested incrementally until the product is finished. |
| 2. | In spiral model requirements and early stage planning is also necessary. | In incremental model requirements and early stage planning is necessary. |
| 3. | Flexibility to change in spiral model is not that difficult. | Flexibility to change in incremental model is Easy. |
| 4. | There is low amount risk in spiral model. | There is also low amount risk in incremental model. |
| 5. | While cost of spiral model is very expensive. | Cost of incremental model is also Low. |
| 6. | Spiral model can handle large project. | Incremental model can’t handle large project. |
| 7. | In spiral model overlapping of phases is not possible. | In incremental model overlapping of phases is possible. |
| 8. | Testing is done in spiral model at the end of the engineering phase. | Testing is done in incremental model after every iteration of phase. |
| 9. | Returning to previous stage/phase in spiral model is possible. | Returning to previous stage/phase in incremental model is possible. |
| 10. | In spiral model large team is required. | In incremental model large team is not required. |